[clang] [clang-tools-extra] [clang] Make "__GCC_HAVE_DWARF2_CFI_ASM" a proper predefined macro (PR #165731)

[Cyndy Ishida via cfe-commits]

cyndyishida wrote:

The remaining test failures are unrelated and currently happening in mainline.
```
Traceback (most recent call last):
  File "/home/tcwg-buildbot/worker/lldb-aarch64-ubuntu/llvm-project/lldb/test/API/dotest.py", line 8, in <module>
    lldbsuite.test.run_suite()
 ...
NameError: name 'skipif' is not defined. Did you mean: 'skipIf'?
```
https://lab.llvm.org/buildbot/#/builders/59/builds/26570/steps/6/logs/stdio

https://github.com/llvm/llvm-project/pull/165731