Use instead of restoring side table for Loop

[zhouwfang]

On my Linux Docker container:

CoreMark results of this PR: 37.991516 (in 18.695s), 36.7287 (in 19.258s)

CoreMark results of #690: 37.101162 (in 19.133s), 37.39716 (in 18.996s)

Look very similar. Not sure about nordic.

CoreMark results of main: 28.791477 (in 18.09s), 28.814291 (in 17.734s)

So there does seem some minor performance improvement with delta_ip and delta_stp.

#46

[ia0]

On nordic I get:

• This pull request (with the suggested changes): 0.13723445 (in 146.037s) and 6660 bytes of RAM
• This development branch: 0.13704263 (in 146.247s) and 7588 of RAM
• The main branch: 0.09060761 (in 221.04s) and 5416 of RAM

So we should merge this PR, not only because it uses less RAM, but also because it simplifies the code.

[zhouwfang]

On nordic I get:

• This pull request (with the suggested changes): 0.13723445 (in 146.037s) and 6660 bytes of RAM
• This development branch: 0.13704263 (in 146.247s) and 7588 of RAM
• The main branch: 0.09060761 (in 221.04s) and 5416 of RAM

So we should merge this PR, not only because it uses less RAM, but also because it simplifies the code.

How do you measure RAM?

[ia0]

How do you measure RAM?

This is specific to Nordic:

wasefire/crates/wasm-bench/src/target/nordic.rs

Line 70 in 15823da

println!("Peak RAM usage: {}", USAGE.load(Ordering::Relaxed));