[compiler-rt] [compiler-rt][AArch64][Android] Use getauxval on Android. (PR #102979)

[Daniel Kiss via llvm-commits]

DanielKristofKiss wrote:

Calling getauxval on Android is fine since:
https://android-review.googlesource.com/c/platform/bionic/+/836525

The [original](https://reviews.llvm.org/D154045#inline-1548473) motivation is broken as compiler-rt does call getauxval a lot from other places as of today.

https://github.com/llvm/llvm-project/pull/102979