Auto merge of #145304 - m-ou-se:simplify-panic, r=oli-obk

Revert "Partially outline code inside the panic! macro".

This reverts https://github.com/rust-lang/rust/pull/115670

Without any tests/benchmarks that show some improvement, it's hard to know whether the change had any positive effect. (And if it did, whether that effect is still achieved today.)