Remove libclang.so

Bug: http://b/64121881

Remove the libclang.so module (and retain libclang_android.so).
Simplify the declarations now that there's only one variant.

Test: aosp_marlin checkbuild with FORCE_BUILD_LLVM_COMPONENTS set and
unset.

Change-Id: I5b2475062982933f2971e788d3f8d05296d170d6
1 file changed