Make libclcore_neon arm32-only

Also a couple of minor clean-ups

Test: build sdk_gphone64_x86_64 and bertha_x86_64 and verify artifacts
are as expected
Bug: 318490289
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:4118974727f0a29d36cdce3fdcdbd8ae30f24817)
Merged-In: I7734a8cd1aae4498e714f7bcd1df5492d8a82986
Change-Id: I7734a8cd1aae4498e714f7bcd1df5492d8a82986
1 file changed