[Wasm GC] Nondeterminism in type emitting

[kripken]

STR: run

wasm-opt a.wasm -all --roundtrip --print | md5sum

many times. Every 30 or so I see two different hashes.

Oddly this doesn't happen with --name-types done before the roundtrip, or with removing the roundtrip.

Two output wats are included in the zip. The diff is a minor ordering change:

11d10
<  (type $ref|{mut:i32_mut:ref?|...0|_mut:i64_mut:i64_mut:i64_mut:ref?|{mut:i32}|}|_ref|{mut:i32}|_=>_none (func (param (ref ${mut:i32_mut:ref?|...0|_mut:i64_mut:i64_mut:i64_mut:ref?|{mut:i32}|}) (ref ${mut:i32}))))
12a12
>  (type $ref|{mut:i32_mut:ref?|...0|_mut:i64_mut:i64_mut:i64_mut:ref?|{mut:i32}|}|_ref|{mut:i32}|_=>_none (func (param (ref ${mut:i32_mut:ref?|...0|_mut:i64_mut:i64_mut:i64_mut:ref?|{mut:i32}|}) (ref ${mut:i32}))))

cc @tlively

test.zip

[tlively]

I suspect this is also due to #3682. I will re-prioritize updating and landing #3793 to fix it.

Edit: fixed copy-paste error with those issue numbers.

[tlively]

This should no longer be a problem.