[profile][test] Fix Profile-* :: instrprof-merge.c etc. on SPARC

While working on https://reviews.llvm.org/D40900 (which effectively is about enabling compiler-rt on sparc these days), I came across two failing profile testcases:

  Profile-sparc :: instrprof-merge-match.test
  Profile-sparc :: instrprof-merge.c
  Profile-sparcv9 :: instrprof-merge-match.test
  Profile-sparcv9 :: instrprof-merge.c

All of them crashed with a SIGBUS in __llvm_profile_merge_from_buffer:

  Thread 2 received signal SIGSEGV, Segmentation fault.
  [Switching to Thread 1 (LWP 1)]
  0x00012368 in __llvm_profile_merge_from_buffer (
      ProfileData=0x2384c <main.Buffer> "\377lprofR\201", ProfileSize=360)
      at /vol/llvm/src/llvm/local/projects/compiler-rt/lib/profile/InstrProfilingMerge.c:95
  95        SrcDataEnd = SrcDataStart + Header->DataSize;

where Header is insufficiently aligned for a strict-alignment target like SPARC.

Fixed by forcing the alignment to uint64_t, the members of struct __llvm_profile_header,
in the callers.

Tested on sparcv9-sun-solaris2.11.

https://reviews.llvm.org/D64498

llvm-svn: 365805