[clang] [Driver] Disable sanitizer ignorelists on Darwin (PR #195690)

[Hans Wennborg via cfe-commits]

zmodem wrote:

> The ignorelists do not contain anything useful for Darwin, and they are causing issues with the (downstream) Swift clang importer.

@ndrewh can you ELI5 what these problems are?

In any case, gating this on the host OS with a CMake flag doesn't seem like a good idea to me. What if someone is cross-compiling for Mac from Linux for example -- shouldn't the ignorelists be ignored then too? And what if someone (hi @compnerd) is building Swift for Windows -- won't they have the same problem with the swift clang importer?

https://github.com/llvm/llvm-project/pull/195690