Revert "cmd/compile/internal/noder: limit the number of goroutine"
Revert "cmd/compile/internal/noder: limit the number of goroutine"

This reverts commit c274a7c03be7b69d54d3307b954f6a0eb298c860.

Reason for revert: this can cause a compiler deadlock, and there's
no demonstrable benefit to making the change.

Change-Id: I42325ddea68d37db16fd0061c5baaee112b755b7
Reviewed-on: https://go-review.googlesource.com/c/go/+/308369
Trust: Matthew Dempsky <e56ac2c500064424afac424d4b5e53bd0570a731@google.com>
Run-TryBot: Matthew Dempsky <e56ac2c500064424afac424d4b5e53bd0570a731@google.com>
Reviewed-by: Robert Griesemer <a6752097faebf1f02d80107d77a9be009089afe3@golang.org>
TryBot-Result: Go Bot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

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