uhv: add http-parser permissive parsing for h1 codec

[ameily]

Commit Message: uhv: add http-parser permissive parsing for h1 codec

Additional Description: Honor the new uhv_enabled build flag to disable strict parsing within the H1 parsing library (http-parser). This is a reworking of the previous PR, #20528, but this time using the new compile-time option instead of making it configurable at runtime.

Risk Level: Low

Testing:

Docs Changes:

Release Notes:

Platform Specific Features:

Fixes #19750

[ameily]

@yanavlasov This should be good for review.

[yanavlasov]

@alyssawilk this is special UHV build for H/1 parser with header validation disabled, using existing #define

[alyssawilk]

Yeah this has my thumbs up, assuming it fails the compile time build without that early return. Mind taking that define out and checking once?
/wait

[ameily]

@alyssawilk I have confirmed that removing the early return in both protocol_integration_test and http_inspector_test results in both failing when UHV is enabled:

[  FAILED  ] Protocols/DownstreamProtocolIntegrationTest.BadRequest/IPv4_HttpDownstream_HttpUpstreamNghttp2NoDeferredProcessing
[  FAILED  ] HttpInspectorTest.MultipleReadsHttp1BadProtocol (156 ms)

[alyssawilk]

Awesome, thanks for confirming.
cc @snowp for !Googler pass

[snowp]

LGTM, thanks!