treewide: Convert bugs.llvm.org links to llvm.org/pr links

LLVM has transitioned from a self-hosted Bugzilla instance to GitHub
Issues. While the links still work, they do not reflect the current
status of issues, as Bugzilla is read only.

Update all of the bugs.llvm.org links to the new llvm.org/pr#, which
takes a Bugzilla ID number and converts it to a GitHub link, as the
numbers did not transfer 1 to 1 due to GitHub issues.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
19 files changed