Reland "Switch from GNU to LLVM based tools."

This is a reland of bf16b335

Original change's description:
> Switch from GNU to LLVM based tools.
>
> Android NDK 23 switched to a LLVM based toolchain. However some LLVM
> based tools like llvm-readobj and llvm-objcopy are available with NDK 22
> already. To prepare the roll to NDK 23, switch to llvm-readobj and
> llvm-copy for Android builds.
>
> Bug: 1246049
> Change-Id: I1cc3cec4aeaa159f6189f810ff6e709879b51204
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3162163


> Reviewed-by: Hans Wennborg <hans@chromium.org>
> Commit-Queue: Richard Townsend <richard.townsend@arm.com>
> Cr-Commit-Position: refs/heads/main@{#922566}

Bug: 1246049
Change-Id: I428f5f8fb19e09e21afd83aec3d9fe80e910b8fe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3168334


Reviewed-by: Hans Wennborg <hans@chromium.org>
Commit-Queue: Richard Townsend <richard.townsend@arm.com>
Cr-Commit-Position: refs/heads/main@{#923362}