cmd/compile: fix wrong instantiated type for embedded receiver
In case of embedded field, if the receiver was fully instantiated, we
must use its instantiated type, instead of passing the type params of
the base receiver.
Fixes #47797
Fixes #48253
Change-Id: I97613e7e669a72605137e82406f7bf5fbb629378
Reviewed-on: https://go-review.googlesource.com/c/go/+/348549
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Trust: Dan Scales <danscales@google.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Dan Scales <danscales@google.com>