[ASTMatchers] Add hasPlacementArg and hasAnyPlacementArg traversal matcher for CXXNewExpr

Summary: Adds new traversal matchers called `hasPlacementArg` and `hasAnyPlacementArg` that matches on arguments to `placement new` operators.

Reviewers: aaron.ballman

Reviewed By: aaron.ballman

Subscribers: merge_guards_bot, mehdi_amini, hiraditya, steven_wu, dexonsmith, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D73562