This is a subset of https://golang.org/cl/20022 with only the copyright
header lines, so the next CL will be smaller and more reviewable.

Go policy has been single space after periods in comments for some time.

The copyright header template at:

    https://golang.org/doc/contribute.html#copyright

also uses a single space.

Make them all consistent.

Change-Id: Icc26c6b8495c3820da6b171ca96a74701b4a01b0
Reviewed-on: https://go-review.googlesource.com/20111
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: I728d4c709c4122fe4b96e1350be73696ac6fb1f7
Reviewed-on: https://go-review.googlesource.com/18422
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Today, signal.Ignore(syscall.SIGTRAP) does nothing
while signal.Notify(make(chan os.Signal), syscall.SIGTRAP)
correctly discards user-generated SIGTRAPs.
The same applies to any signal that we throw on.

Make signal.Ignore work for these signals.

Fixes #12906.

Change-Id: Iba244813051e0ce23fa32fbad3e3fa596a941094
Reviewed-on: https://go-review.googlesource.com/18348
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Now there are just three programs to compile instead of many,
and repeated tests can reuse the compilation result instead of
rebuilding it.

Combined, these changes reduce the time spent testing runtime
during all.bash on my laptop from about 60 to about 30 seconds.
(All.bash itself runs in 5½ minutes.)

For #10571.

Change-Id: Ie2c1798b847f1a635a860d11dcdab14375319ae9
Reviewed-on: https://go-review.googlesource.com/18085
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>