[dev.typeparams] cmd/compile: delay method value wrapper generation until walk

As walk already create the wrapper if necessary.

With this change, test/inline.go need to be changed to use
errorcheckwithauto, for matching "inlining call to ..." in autogenerated
position for method value wrapper, since when we don't generate the
wrapper immediately during typecheck.

Change-Id: I9ffbec9ad3c2b7295546976e2fa517336c13c89b
Reviewed-on: https://go-review.googlesource.com/c/go/+/330838


Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>