As indicated by the tests, it is possible to feed the AsmParser an
invalid datalayout string. We should verify the result of parsing this
string regardless of whether or not we have assertions enabled.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223898 91177308-0d34-0410-b5e6-96231b3b80d8
