Rollup merge of #130077 - madsmtm:watchos-arm-unwind, r=workingjubilee

Fix linking error when compiling for 32-bit watchOS

In rust-lang/rust#124494 (or rust-lang/rust#124748), I mistakenly conflated "not SjLj" to mean "ARM EHABI", which isn't true, 32-bit watchOS uses a third unwinding method called "DWARF CFI".

So this PR is effectively a revert of rust-lang/rust#124494, with a few more comments explaining what's going on.

Fixes rust-lang/rust#130071.

r? Mark-Simulacrum (since you reviewed the original)