Fix isIntegerConstantExpr eval of __builtin_offsetof to return result
with correct width.
 - PR2728.

Also, fix PR2727 test case.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@55493 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed