ci: enble LLVM download for windows-gnu hosts

src/ci/github-actions/jobs.yml

@@ -426,18 +426,12 @@ auto:
     env:
       RUST_CONFIGURE_ARGS: --build=i686-pc-windows-gnu
       SCRIPT: make ci-mingw
-      # We are intentionally allowing an old toolchain on this builder (and that's
-      # incompatible with LLVM downloads today).
-      NO_DOWNLOAD_CI_LLVM: 1
     <<: *job-windows-8c
 
   - image: x86_64-mingw
     env:
       SCRIPT: make ci-mingw
       RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-gnu
-      # We are intentionally allowing an old toolchain on this builder (and that's
-      # incompatible with LLVM downloads today).
-      NO_DOWNLOAD_CI_LLVM: 1
     <<: *job-windows-8c
 
   - image: dist-x86_64-msvc
@@ -484,9 +478,6 @@ auto:
       RUST_CONFIGURE_ARGS: >-
         --build=i686-pc-windows-gnu
         --enable-full-tools
-      # We are intentionally allowing an old toolchain on this builder (and that's
-      # incompatible with LLVM downloads today).
-      NO_DOWNLOAD_CI_LLVM: 1
       SCRIPT: python x.py dist bootstrap --include-default-paths
       DIST_REQUIRE_ALL_TOOLS: 1
       CODEGEN_BACKENDS: llvm,cranelift
@@ -498,9 +489,6 @@ auto:
       RUST_CONFIGURE_ARGS: >-
         --build=x86_64-pc-windows-gnu
         --enable-full-tools
-      # We are intentionally allowing an old toolchain on this builder (and that's
-      # incompatible with LLVM downloads today).
-      NO_DOWNLOAD_CI_LLVM: 1
       DIST_REQUIRE_ALL_TOOLS: 1
       CODEGEN_BACKENDS: llvm,cranelift
     <<: *job-windows