Avoid conflicts between architectures in prebuilt_renderscript_bitcode

The NDK build has 4 architectures, x86 and arm 32-bit architectures and
x86_64 and arm64 64-bit architectures.  Multilib on its own is not
enough to prevent collisions in install locations.  Detect conflicts
and add the architecture to the path the same way cc/installer.go does.

Bug: 308212344
Test: OUT_DIR=out build/soong/scripts/build-ndk-prebuilts.sh
Change-Id: If7a1b062035dda87f5f8129062778c41c43de17b