Disable deprecated-copy warnings on various LLVM code to bring the bot back to green

Bootstrap with `-Werror` is currently broken due to D79714.
This patch is required to bring the bootstrap bot back to green. The
code will likely need to be fixed and the pragmas removed in due time,
but for now we need to bring the bot back up.

Bot that is currently failing:
https://lab.llvm.org/buildbot/#/builders/36/builds/7680

Differential Revision: https://reviews.llvm.org/D101214