all: use built-in clear to clear maps
Change-Id: I7f4ac72fe3230d8b7486fab0c925015cefcbe355
GitHub-Last-Rev:
54455839b674f980fb6c3afceb433db4833d340e
GitHub-Pull-Request: golang/go#61544
Reviewed-on: https://go-review.googlesource.com/c/go/+/512376
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>