FORCE_BUILD_LLVM_COMPONENTS if HOST_PREFER_32_BIT.

Because we don't have 32-bit prebuilt libLLVM/libclang.

Change-Id: I86dac33e9bcbcb3d197f7d1e4c9d33bd4e7c473e
Merge "FORCE_BUILD_LLVM_COMPONENTS if HOST_PREFER_32_BIT."