Option<bool>::eq optimizes poorly

[scottmcm]

Option<bool>::eq is ~20 lines of assembly as of rustc 1.87.0-nightly (a2e63569f 2025-03-26).

Repro: https://rust.godbolt.org/z/hPn8TvvYP

This is here to track this FIXME:

rust/tests/codegen/option-niche-eq.rs

Lines 65 to 73 in 2a06022

	// FIXME: This should work too
	// // FIXME-CHECK-LABEL: @bool_eq
	// #[no_mangle]
	// pub fn bool_eq(l: Option<bool>, r: Option<bool>) -> bool {
	// // FIXME-CHECK: start:
	// // FIXME-CHECK-NEXT: icmp eq i8
	// // FIXME-CHECK-NEXT: ret i1
	// l == r
	// }

With llvm/llvm-project#133344 fixed upstream (thanks @veera-sivarajan for jumping on it so quickly!) after the LLVM 21 version upgrade we should revisit this and see whether we can enable that test.