Delete handling for --x-use-aria2, avoid duplicate file hashing, and fix hash mismatch message.

[BillyONeal]

Related microsoft/vcpkg-tool#1582

In microsoft/vcpkg-tool#1580 (comment) I discovered that the existing hash mismatch message was entirely broken.

Also fixed that whenever we had an existing download with a matching SHA, we were SHA512-ing it twice.

It seems like the existing _VCPKG_INTERNAL_NO_HASH_CHECK is broken as the only place it is used is for updating qt, and for those cases not trying to download a current version seems like an error, but I've kept the existing behavior. /cc @Neumann-A

Example new output:

CMake Error at scripts/cmake/vcpkg_download_distfile.cmake:93 (message):
    D:/vcpkg-downloads/madler-zlib-v1-8c964249.3.1.tar.gz: error: existing downloaded file had an unexpected hash
    Expected: 8c9642495bafd6fad4ab9fb67f09b268c69ff9af0f4f20cf15dfc18852ff1f312bd8ca41de761b3f8d8e90e77d79f2ccacd3d4c5b19e475ecf09d021fdfe9087
    Actual  : 8c9642495bafd6fad4ab9fb67f09b268c69ff9af0f4f20cf15dfc18852ff1f312bd8ca41de761b3f8d8e90e77d79f2ccacd3d4c5b19e475ecf09d021fdfe9088
    note: You may be able to resolve this failure by redownloading the file. To do so, delete D:/vcpkg-downloads/madler-zlib-v1-8c964249.3.1.tar.gz and retry.
Call Stack (most recent call first):

... now matches the current tool output in the download case except for the 'note's. (I would put the note:s there, but CMake already makes emitting reasonable errors here impossible by forcing things to be indented :( )

Downloading https://github.com/madler/zlib/archive/v1.3.1.tar.gz -> madler-zlib-v1-8c964249.3.1.tar.gz
D:\vcpkg-downloads\madler-zlib-v1-8c964249.3.1.tar.gz.28932.part: error: download from https://github.com/madler/zlib/archive/v1.3.1.tar.gz had an unexpected hash
note: Expected: 8c9642495bafd6fad4ab9fb67f09b268c69ff9af0f4f20cf15dfc18852ff1f312bd8ca41de761b3f8d8e90e77d79f2ccacd3d4c5b19e475ecf09d021fdfe9087
note: Actual  : 8c9642495bafd6fad4ab9fb67f09b268c69ff9af0f4f20cf15dfc18852ff1f312bd8ca41de761b3f8d8e90e77d79f2ccacd3d4c5b19e475ecf09d021fdfe9088

As an aside, I think there's an argument that the 'existing file' handling belongs in x-download, rather than here in CMake, but as that affects a documented interface I'm not looking to make such a change right now.

[BillyONeal]

REGRESSION: angle:arm64-osx failed with BUILD_FAILED. If expected, add angle:arm64-osx=fail to /Users/vcpkg/Data/work/2/s/scripts/azure-pipelines/../ci.baseline.txt.
REGRESSION: angle:x64-osx failed with BUILD_FAILED. If expected, add angle:x64-osx=fail to /Users/vcpkg/Data/work/1/s/scripts/azure-pipelines/../ci.baseline.txt.

CMake Error at cmake/WebKitCommon-minimal.cmake:171 (include):
  include could not find requested file:

    WebKitMacros
Call Stack (most recent call first):
  CMakeLists.txt:5 (include)


CMake Error at cmake/WebKitCommon-minimal.cmake:174 (include):
  include could not find requested file:

    WebKitCompilerFlags
Call Stack (most recent call first):
  CMakeLists.txt:5 (include)


-- Found ZLIB: optimized;/Users/vcpkg/Data/installed/x64-osx/lib/libz.a;debug;/Users/vcpkg/Data/installed/x64-osx/debug/lib/libz.a (found version "1.3.1")
CMake Error at CMakeLists.txt:245 (WEBKIT_INCLUDE_CONFIG_FILES_IF_EXISTS):
  Unknown CMake command "WEBKIT_INCLUDE_CONFIG_FILES_IF_EXISTS".

This looks like a missing dependency declaration?

REGRESSION: mesa:x64-windows-static-md failed with BUILD_FAILED. If expected, add mesa:x64-windows-static-md=fail to D:\a_work\1\s\scripts\azure-pipelines/../ci.baseline.txt.

This looks like the %temp% race again, bison crashed.

REGRESSION: paraview:arm64-osx failed with BUILD_FAILED. If expected, add paraview:arm64-osx=fail to /Users/vcpkg/Data/work/2/s/scripts/azure-pipelines/../ci.baseline.txt.
REGRESSION: paraview:x64-osx failed with BUILD_FAILED. If expected, add paraview:x64-osx=fail to /Users/vcpkg/Data/work/1/s/scripts/azure-pipelines/../ci.baseline.txt.

Trying to download paraview_external_vtk_pr-c7760599.diff using asset cache https://vcpkgassetcachewus.blob.core.windows.net/cache/c7760599239334817e9cad33ab7019c2dd0ce6740891e10ec15e1d63605ad73095fd7d48aed5ca8d002d25db356a7a5cf2a37188f0b43a7a9fa4c339e8f42adb?*** SECRET ***
Download successful! Asset cache hit, did not try authoritative source https://gitlab.kitware.com/paraview/paraview/-/merge_requests/6375.diff?full_index=1
CMake Error at scripts/cmake/vcpkg_replace_string.cmake:12 (file):
  file failed to open for reading (No such file or directory):

    /Users/vcpkg/Data/b/paraview/paraview_external_vtk_pr.diff
Call Stack (most recent call first):
  ports/paraview/portfile.cmake:32 (vcpkg_replace_string)
  scripts/ports.cmake:196 (include)

Hmmmm looks like I missed a MAKE_DIRECTORY.

REGRESSION: vcpkg-tool-python2:x64-windows-static failed with BUILD_FAILED. If expected, add vcpkg-tool-python2:x64-windows-static=fail to D:\a_work\1\s\scripts\azure-pipelines/../ci.baseline.txt.
REGRESSION: vcpkg-tool-python2:x64-windows-static-md failed with BUILD_FAILED. If expected, add vcpkg-tool-python2:x64-windows-static-md=fail to D:\a_work\1\s\scripts\azure-pipelines/../ci.baseline.txt.

CMake Error at ports/vcpkg-tool-python2/portfile.cmake:41 (file):
  file RENAME failed to rename

    D:/p/vcpkg-tool-python2_x64-windows-static-md/manual-tools/python-2.7.18.amd64/SourceDir/

  to

    D:/p/vcpkg-tool-python2_x64-windows-static-md/manual-tools/vcpkg-tool-python2/

  because: The system cannot find the path specified.