[llvm] RuntimeLibcalls: Really move default libcall handling to tablegen (PR #148780)

[Nikita Popov via llvm-commits]

https://github.com/nikic approved this pull request.

LGTM. Looks like the behavior changes on AVR, MSP430 and XCore are intentional.

https://github.com/llvm/llvm-project/pull/148780