[clang] roll-forward "[clang] Mark `trivial_abi` types as "trivially relocatable"".

This reverts commit 852afed5.

Changes since D114732:

On PS4, we reverse the expectation that classes whose constructor is deleted are not trivially relocatable. Because, at the moment, only classes which are passed in registers are trivially relocatable, and PS4 allows passing in registers if the copy constructor is deleted, the original assertions were broken on PS4.

(This is kinda similar to DR1734.)

Reviewed By: gribozavr2

Differential Revision: https://reviews.llvm.org/D119017