[ubsan] PR33081: Skip the standard type checks for volatile

Skip checks for null dereference, alignment violation, object size
violation, and dynamic type violation if the pointer points to volatile
data.

Differential Revision: https://reviews.llvm.org/D34262

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@305546 91177308-0d34-0410-b5e6-96231b3b80d8