Revert "Sema: forbid @breakpoint from being called at comptime"

This reverts commit f88b523065fbb8afbd723fd6e803ace0334b713c.

Let's please go through the language proposal process for this change. I
don't see any justification for this breaking change even in the commit
message.
3d23ba9c35Andrew Kelley committed on 12/11/2023, 7:24:15 PMparentf88b523
4 files changedLine totals unavailable