[Clang] Remove unwanted --check-prefix=CHECK from unit tests. NFC.

Summary:
    Removed unwanted --check-prefix=CHECK from the following unit tests:
      test/CXX/special/class.copy/implicit-move-def.cpp
      test/CodeGen/cleanup-destslot-simple.c
      test/CodeGen/inline-asm-immediate-ubsan.c
      test/CodeGen/mips-interrupt-attr.c
      test/CodeGenCXX/cfi-stats.cpp
      test/CodeGenCXX/copy-constructor-elim.cpp
      test/CodeGenCXX/microsoft-templ-uuidof.cpp
      test/CodeGenCXX/vtable-linkage.cpp
      test/CodeGenObjC/messages-2.m
      test/Driver/noinline.c
      test/Index/remap-load.c
      test/Index/retain-comments-from-system-headers.c
      test/OpenMP/task_if_codegen.cpp
      test/Preprocessor/comment_save_macro.c

Patch by:  Mandeep Singh Grang (mgrang)

Reviewers: rafael, ABataev, rengolin

Projects: #clang-c

Differential Revision: http://reviews.llvm.org/D19232

llvm-svn: 266843