Do not link libLLVM.so into libbcinfo.so

Bug: http://b/28866258

For the on-device libbcinfo.so, statically link required LLVM static
libraries into libbcinfo.so and export just the symbols in the bcinfo
namespace.

After this change, libLLVM.so should no longer get loaded during zygote
initialization.  libbcinfo.so increases by roughly 700K for 32-bit and
900K for 64-bit.

Test: RenderScript CTS tests on Angler and libbcc lit tests pass (except
for 1 known failure)

Change-Id: If2f07336b09028b113086987f3ff02520b6aef92