[test-suite] There is no such thing as CMAKE_C_CFLAGS, it's CMAKE_C_FLAGS

Summary: Noticed by accident.

Reviewers: homerdin, MatzeB, hfinkel, fhahn

Reviewed By: fhahn

Subscribers: fhahn, mgorny, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60215

llvm-svn: 358084
1 file changed