crypto/tls: fix flakey test.

A test added in b37d2fdcc4d9 didn't work with some values of GOMAXPROCS
because the defer statements were in the wrong order: the Pipe could be
closed before the TLS Client was.

R=golang-dev, bradfitz
CC=golang-dev
https://codereview.appspot.com/9187047
runtime: fix scanning of not started goroutines

The stack scanner for not started goroutines ignored the arguments
area when its size was unknown.  With this change, the distance
between the stack pointer and the stack base will be used instead.

Fixes issue 5486

R=golang-dev, bradfitz, iant, dvyukov
CC=golang-dev
https://codereview.appspot.com/9440043
runtime: do not mark os memory as executable on windows

R=golang-dev, bradfitz, khr
CC=golang-dev
https://codereview.appspot.com/9235046
runtime: revert 3c2cddfbdaec

It appears, syscall.NewCallback still
uses heap to store executable code.

R=golang-dev, khr
CC=golang-dev
https://codereview.appspot.com/9060046
os: clarify windows read console code

R=golang-dev, r
CC=golang-dev
https://codereview.appspot.com/9458043
cmd/ld: emit .tbss section when doing dynamic internal linking
Fixes issue 5200.

R=iant, dave
CC=golang-dev
https://codereview.appspot.com/9383043
misc/cgo/test: deflake TestParallelSleep once more
Fixes issue 5480.

R=golang-dev, iant
CC=golang-dev
https://codereview.appspot.com/9475043
runtime: faster x86 memmove (a.k.a. built-in copy())

REP instructions have a high startup cost, so we handle small
sizes with some straightline code.  The REP MOVSx instructions
are really fast for large sizes.  The cutover is approximately
1K.  We implement up to 128/256 because that is the maximum
SSE register load (loading all data into registers before any
stores lets us ignore copy direction).

(on a Sandy Bridge E5-1650 @ 3.20GHz)
benchmark               old ns/op    new ns/op    delta
BenchmarkMemmove0               3            3   +0.86%
BenchmarkMemmove1               5            5   +5.40%
BenchmarkMemmove2              18            8  -56.84%
BenchmarkMemmove3              18            7  -58.45%
BenchmarkMemmove4              36            7  -78.63%
BenchmarkMemmove5              36            8  -77.91%
BenchmarkMemmove6              36            8  -77.76%
BenchmarkMemmove7              36            8  -77.82%
BenchmarkMemmove8              18            8  -56.33%
BenchmarkMemmove9              18            7  -58.34%
BenchmarkMemmove10             18            7  -58.34%
BenchmarkMemmove11             18            7  -58.45%
BenchmarkMemmove12             36            7  -78.51%
BenchmarkMemmove13             36            7  -78.48%
BenchmarkMemmove14             36            7  -78.56%
BenchmarkMemmove15             36            7  -78.56%
BenchmarkMemmove16             18            7  -58.24%
BenchmarkMemmove32             18            8  -54.33%
BenchmarkMemmove64             18            8  -53.37%
BenchmarkMemmove128            20            9  -55.93%
BenchmarkMemmove256            25           11  -55.16%
BenchmarkMemmove512            33           33   -1.19%
BenchmarkMemmove1024           43           44   +2.06%
BenchmarkMemmove2048           61           61   +0.16%
BenchmarkMemmove4096           95           95   +0.00%

R=golang-dev, bradfitz, remyoudompheng, khr, iant, dominik.honnef
CC=golang-dev
https://codereview.appspot.com/9038048
cmd/vet: delete; it now lives in the go.tools subrepo

R=golang-dev, dsymonds, rsc, iant, dave
CC=golang-dev
https://codereview.appspot.com/9496043