[clang] [clang] Enable -fstack-clash-protection by default for Android (PR #209279)

[Corentin Jabot via cfe-commits]

cor3ntin wrote:

I think we can
 - simplify the test
 - simplify - GREATLY - the commit message.
 - And then land this, Given it has approval of the community, android maintainers, and the clang area team 

Here is a possible rewrite of the description/commit message.

> ### [clang] Enable -fstack-clash-protection by default for Android
> Enable -fstack-clash-protection by default for Android targets on
architectures where Clang already supports stack clash protection, as per the RFC
https://discourse.llvm.org/t/rfc-enable-fstack-clash-protection-by-default-for-android-targets/91223

You really do not need to say more.

Thanks

https://github.com/llvm/llvm-project/pull/209279