Revert "cmd/compile: improve equality algs for arrays of interfaces"
Revert "cmd/compile: improve equality algs for arrays of interfaces"

This reverts commit 7eab9506c92562fe49861597e7bf1fcb28f2fd40.

Reason for revert: Undoing to get back to semantics discussed in #8606.

Change-Id: If0cd7518c10c37a81fdbb4ae112239e04c0b1448
Reviewed-on: https://go-review.googlesource.com/c/go/+/236278
Run-TryBot: Keith Randall <8c99c3a9284e493be632950b84cd789d08ed3e9d@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Matthew Dempsky <e56ac2c500064424afac424d4b5e53bd0570a731@google.com>

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