Unbreak the sanitizer buildbots after r209226 due to SROA issue described in http...

Unbreak the sanitizer buildbots after r209226 due to SROA issue described in reviews.llvm.org/D3714

Undecided whether this should include a test case - SROA produces bad
dbg.value metadata describing a value for a reference that is actually
the value of the thing the reference refers to. For now, loosening the
assert lets this not assert, but it's still bogus/wrong output...

If someone wants to tell me to add a test, I'm willing/able, just
undecided. Hopefully we'll get SROA fixed soon & we can tighten up this
assertion again.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209240 91177308-0d34-0410-b5e6-96231b3b80d8