Update llvm-cm against recent LLVM changes

[boomanaiden154]

llvm-cm needs to be updated to reflect some recent LLVM changes:

• BBRanges are now used to represent the basic blocks in a function. llvm-cm needs to support these for cases like basic block sections and split machine functions (and should at the very least have test coverage for them).
• -mbb-profile-dump no longer exists, and instead PGOAnalysisMap should be used. Tests/code needs to be updated for this.

This (at least the second part) is sort of a prerequisite for #55.