Pass a concrete triple for two OpenMP tests that depend on TLS

Not all %itanium_abi_triple values support TLS. Makes
OpenMP/declare_reduction_codegen.cpp, OpenMP/parallel_copyin_codegen.cpp for
%itanium_abi_triples without TLS support.

Alternatively we could pass -fnoopenmp-use-tls and tweak some of the CHECK
lines, but this seems a bit simpler.

Fixes PR40156.

Differential Revision: https://reviews.llvm.org/D56086

llvm-svn: 350067