[Renderscript] Explicitly set the language to evaluate allocations

Currently it is not specified, and since allocations are usually
requested once we hit a renderscript breakpoint, the language will be
inferred being as renderscript by the ExpressionParser.
Actually allocations attempt to invoke functions part of the RS runtime,
written in C/C++, so evaluating the calls in RenderScript could be
misleading.

In particular, in MIPS, the ABI between C/C++ (mips o32) and
renderscript (arm) might introduce subtle bugs when evaluating such
expressions.

This change explicitly sets the language used to evaluate the allocations
as C++.

Committed on behalf of: Dean De Leo <dean@codeplay.com>

llvm-svn: 263129