[TableGen] Fix negation of simple predicates

Simple predicates, such as those defined by `CheckRegOperandSimple` or
`CheckImmOperandSimple`, were not being negated when used with `CheckNot`.

This change fixes this issue by defining the previously declared methods to
handle simple predicates.

Differential revision: https://reviews.llvm.org/D55089

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@348034 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed