This reverts commit 5a457837dd988aa01c65820848381a5b99a74c0a.
Includes the test fix from
https://github.com/llvm/llvm-project/pull/177659.
The test had to be updated to exclude a scenario that was failing
with/without the change (involving mapping a struct with a byref member
with a mapper).
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**Original PR's description:**
This is a fix for https://github.com/llvm/llvm-project/issues/61636.
Ravi had this implemented downstream before he retired. This PR is a
chery-pick of that.
The test is taken from @jdoerfert's WIP change in
527bf4b129.
The change partially undoes the changes done in
0caf736d7e1d16d1059553fc28dbac31f0b9f788, so @alexey-bataev might need
to take a look.
339f779570