cmd/compile,cmd/gofmt: use reflect.TypeFor
Use "reflect.TypeFor" to simplify the code.
Updates #60088
Change-Id: I93db6cbd4f02813d9a81f5d02996db8128cb81a9
GitHub-Last-Rev:
2aee64dac6e13ef869aa73f2abf236650e1c1757
GitHub-Pull-Request: golang/go#75349
Reviewed-on: https://go-review.googlesource.com/c/go/+/701676
Reviewed-by: Mark Freeman <markfreeman@google.com>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>