[dev.regabi] cmd/compile: remove okAs
[dev.regabi] cmd/compile: remove okAs

The check for blank in okAs is redundant with what its callers already
done, so just inline the conversion in callers side instead.

Passes toolstash-check.

Change-Id: I606105e2d2cf8e80214722a13c3101c464d20d82
Reviewed-on: https://go-review.googlesource.com/c/go/+/274793
Trust: Cuong Manh Le <54b4457f1dff6823379654eb5867596497ba782f@gmail.com>
Run-TryBot: Cuong Manh Le <54b4457f1dff6823379654eb5867596497ba782f@gmail.com>
TryBot-Result: Go Bot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Matthew Dempsky <e56ac2c500064424afac424d4b5e53bd0570a731@google.com>

cloudflare/go,CAFxX/go,CAFxX/go,golang/go,nawawi/go,golang/go,nawawi/go,nawawi/go,nawawi/go,golang/go,cloudflare/go,CAFxX/go,cloudflare/go,golang/go,CAFxX/go,nawawi/go,cloudflare/go,golang/go,nawawi/go,cloudflare/go,CAFxX/go,nawawi/go,cloudflare/go,cloudflare/go,nawawi/go,golang/go,CAFxX/go,golang/go,CAFxX/go,golang/go,cloudflare/go,CAFxX/go