testing: add TB, an interface common to T and B

R=golang-dev, kevlar, rsc, adg, r
CC=golang-dev
https://codereview.appspot.com/12962043
archive/zip: speed up Zip64 test

Took 76 seconds or so before. By avoiding flate and crc32 on
4GB of data, it's now only 12 seconds.  Still a slow test, but
not painful to run anymore when you forget -short.

R=golang-dev, adg
CC=golang-dev
https://codereview.appspot.com/12950043
time: expand acceptance of time zones when parsing
I tried to make it absolutely correct but there are too many
conflicting definitions for the official list of time zones.
Since when we're parsing we know when to expect
a time zone and we know what they look like if not exactly
what the definitive set is, we compromise. We accept any
three-character sequence of upper case letters, possibly
followed by a capital T (all four-letter zones end in T).

There is one crazy special case (ChST) and the possibility
of a signed hour offset for GMT.

Fixes issue 3790
I hope forever, but I doubt that very much.

R=golang-dev, adg
CC=golang-dev
https://codereview.appspot.com/12969043
net: rearrange the call order of runtime-integrated network pollster and syscall functions

This CL rearranges the call order for raw networking primitives like
the following;

- For dialers that open active connections, pollDesc.Init will be
  called before syscall.Connect.

- For stream listeners that open passive stream connections,
  pollDesc.Init will be called just after syscall.Listen.

- For datagram listeners that open datagram connections,
  pollDesc.Init will be called just after syscall.Bind.

This is in preparation for runtime-integrated network pollster for BSD
variants.

Update issue 5199

R=golang-dev, alex.brainman
CC=golang-dev
https://codereview.appspot.com/12730043
doc: update go1.2.txt

R=golang-dev, bradfitz
CC=golang-dev
https://codereview.appspot.com/12960043
runtime: fix plan9 build

R=golang-dev, r
CC=golang-dev
https://codereview.appspot.com/12986043
runtime: remove old preemption checks
runtime.gcwaiting checks are not needed anymore

R=golang-dev, khr
CC=golang-dev
https://codereview.appspot.com/12934043