Reland "[ASTMatchers] Output currently matching node on crash"

Extend D120185 to also log the node being matched on in case of a crash.
This can help if a matcher is causing a crash or there are not enough interesting nodes bound.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D122529

This reverts commit 61d67c8e.

This relands commit 6e33e45b.

Fixing the build issue on 32bit machines due to not enough free bits in the PointerUnion.