Add a debuginfo version check for RenderScript modules

Added an extra field parser to the `RSModuleDescriptor` class enabling us to
check whether the versions of LLVM used to generated the debug symbols match
across the RenderScript compiler frontend (llvm-rs-cc) and backend (bcc); if
they do not, we warn the user that the debugging experience may be suboptimal
as LLVM IR debug information has no compatibility guarantees.

llvm-svn: 290957