[dev.typeparams] cmd/compile: enable register args on ARM64
[dev.typeparams] cmd/compile: enable register args on ARM64

Now it will be used for functions marked go:registerparams.

test/abi tests are passing with it.

Change-Id: I5af37ae6b79a1064832a42c7ef5f2cc0b5b6a342
Reviewed-on: https://go-review.googlesource.com/c/go/+/322854
Trust: Cherry Mui <d62e63aa42ce272d7b6a5055d97e942b33a34679@google.com>
Run-TryBot: Cherry Mui <d62e63aa42ce272d7b6a5055d97e942b33a34679@google.com>
TryBot-Result: Go Bot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: David Chase <ae171625adc8645b8b79b7e405a6da5aba5341e0@google.com>
Reviewed-by: Than McIntosh <4b2922593166fc595a9b1a408f34f5d3817fe9d2@google.com>

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