Missing tautological compare warnings due to unary operators

The patch mainly focuses on the no warnings for -Wtautological-compare.
It work fine for the positive numbers but doesn't for the negative
numbers. This is because the warning explicitly checks for an
IntegerLiteral AST node, but -1 is represented by a UnaryOperator with
an IntegerLiteral sub-Expr.

Fixes #42918
Differential Revision: https://reviews.llvm.org/D130510