reflect: more function layout tests

Test more stuff:
1) flagNoPointers, an incorrect value was the cause of #9425
2) Total function layout size
3) gc program

Change-Id: I73f65fe740215938fa930d2f096febd9db0a0021
Reviewed-on: https://go-review.googlesource.com/2090
Reviewed-by: Ian Lance Taylor <iant@golang.org>