Rollup merge of #120773 - Enselic:copy-vs-move, r=oli-obk

large_assignments: Allow moves into functions

Moves into functions are typically implemented with pointer passing
rather than memcpy's at the llvm-ir level, so allow moves into
functions.

Part of the "Differentiate between Operand::Move and Operand::Copy" step of rust-lang/rust#83518.

r? `@oli-obk` (who I think is still E-mentor?)