Autogenerate compile tests for INIT macros

[kainino0x]

Replace the manually-maintained INIT test lines with autogenerated tests. Used a quick hack in perl (only tool I could find that could do this easily), it just finds all the INIT macros defined in the header and outputs a test for each one.

It's checked into the repo (instead of generated during build) so that I don't have to deal with making it work on the Windows compile test.

This should have caught some missing items in #580

[lokokung]

Fine to have this as is for now, but it should be fairly simple to make a template + generator to do this and add a presubmit check for it as well. Otherwise, this will just get out of date when/if we add new structs.

[kainino0x]

It's regenerated by make gen and checked for freshness on presubmit just like webgpu.h. I just did it with Perl instead of making a new output file from the Go generator because it was simpler.

[lokokung]

Ooo, sorry I didn't catch that on the first pass. Makes sense! Thanks!