Enable simpler header name parser in debug builds

[ibraheemdev]

This shaves close to a second off debug builds on my machine.

[hawkw]

If we're going to do this, it seems like it might also be a good idea to add a CI step to run the tests in release mode? Otherwsie, most of the parser code is no longer tested on CI.

[seanmonstar]

Maybe I'm misunderstanding... Seems this is turning off the debug assertions?

[ibraheemdev]

It makes it so the simpler version of parse_hdr in any debug builds, instead of only in WASM debug builds. debug_assertions is the cfg flag that identifies a debug build (ish).

[seanmonstar]

I'd normally think in a debug build we'd want the extra checks.

[jeddenlea]

#499 removes the eq macro in all cases.

[ibraheemdev]

Closing in favor of #499.