pulley: Move `fp`/`lr` out of `XReg` set #27082

Job	Run time
Rustfmt	31s
Check JS	7s
Clang format	15s
Determine CI jobs to run	11s
wasmtime-fiber tests	27s
Check wasmtime	4m 10s
Check wasmtime-fiber	28s
Check wasmtime-cli	3m 29s
Check cranelift-codegen	1m 5s
Check wasmtime-bench-api	1m 17s
Check wasmtime-c-api	1m 10s
Check illumos	2m 48s
Clippy	5m 18s
Monolith Checks	3m 26s
no_std checks	48s
Cargo deny	0s
Cargo vet	0s
Doc build	0s
Nightly tests	6m 6s
Tests on i686-unknown-linux-gnu	2m 16s
Tests on i686-unknown-linux-gnu	4m 19s
Check Windows ARM64	0s
Tests on armv7-unknown-linux-gnueabihf	4m 40s
Test C-API ${{ matrix.os }}	0s
Tests on armv7-unknown-linux-gnueabihf	8m 2s
Test wasmtime-fuzzing	0s
Test wasi-nn (${{ matrix.feature }}, ${{ matrix.os }})	0s
Build wasi-preview1-component-adapter	0s
Build wasmtime-target-wasm32	0s
Test DWARF debugging	0s
Test the min-platform example	0s
Run benchmarks	0s
Meta deterministic check	0s
Miri (wasmtime --features pulley)	5m 58s
Miri (wasmtime-cli)	15m 40s
verify-publish	0s
Miri (wasmtime-environ --all-features)	1m 13s
Miri (pulley-interpreter --all-features)	2m 33s
Release build for ${{ matrix.build }}	0s
Cargo vet failed on a Pull Request	0s
Build wasi-preview1-component-adapter-provider	0s
Record the result of testing and building steps	1s
push-tag	0s
	1h 16m 18s

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