Revert "[AST] Put TypeLocs and NestedNameSpecifierLocs into the ParentMap."
Putting DynTypedNode in the ParentMap bloats its memory foot print.
Before the void* key had 8 bytes, now we're at 40 bytes per key which
can mean multiple gigabytes increase for large ASTs and this count
doesn't even include all the added TypeLoc nodes. Revert until I come
up with a better data structure.
This reverts commit r250831.