Speculatively re-apply "[analyzer] MoveChecker: Add checks for dereferencing..."

This re-applies commit r349226 that was reverted in r349233 due to failures
on clang-x64-windows-msvc.

Specify enum type as unsigned for use in bit field. Otherwise overflows
may cause UB.

Differential Revision: https://reviews.llvm.org/D55388

llvm-svn: 349326