runtime: unify C->Go ABI transitions on arm64

runtime: unify C->Go ABI transitions on arm64

There are several of places that save and restore the C callee-saved registers,
the operation is the same everywhere, so this CL defines several macros
to do this, which will help reduce code redundancy and unify the operation.

This CL also replaced consecutive MOVD instructions with STP and LDP instructions
in several places where these macros do not apply.

Change-Id: I815f39fe484a9ab9b6bd157dfcbc8ad99c1420fe
Reviewed-on: https://go-review.googlesource.com/c/go/+/374397
Trust: Eric Fang <eric.fang@arm.com>
Run-TryBot: Eric Fang <eric.fang@arm.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>