[clang] [Clang] Add fake use emission to Clang with -fextend-lifetimes (PR #110102)

[Stephen Tozer via cfe-commits]

SLTozer wrote:

As with the previous commit #110000, this has been merged in [4424c44c](https://github.com/llvm/llvm-project/commit/4424c44c8c4ec8e071f5c5999fba216d36fb92c9), via command line so as to provide proper commit author attribution to @wolfy1961 (as this doesn't seem to be possible via the web interface).

I'm currently looking at a couple buildbot errors; one build failure on several sanitizer bots due to using a deprecated function (trivial update should fix), one test failure on a clang-armv8 bot that at-a-glance looks like the test might be assuming things about the output that aren't true for all arches.

https://github.com/llvm/llvm-project/pull/110102