runtime: update URL for heap dump format

I just created that redirect, so we can change
it once the wiki moves.

LGTM=bradfitz, khr
R=khr, bradfitz
CC=golang-codereviews
https://codereview.appspot.com/177780043
runtime: fix sudog leak

The SudoG used to sit on the stack, so it was cheap to allocated
and didn't need to be cleaned up when finished.

For the conversion to Go, we had to move sudog off the stack
for a few reasons, so we added a cache of recently used sudogs
to keep allocation cheap. But we didn't add any of the necessary
cleanup before adding a SudoG to the new cache, and so the cached
SudoGs had stale pointers inside them that have caused all sorts
of awful, hard to debug problems.

CL 155760043 made sure SudoG.elem is cleaned up.
CL 150520043 made sure SudoG.selectdone is cleaned up.

This CL makes sure SudoG.next, SudoG.prev, and SudoG.waitlink
are cleaned up. I should have done this when I did the other two
fields; instead I wasted a week tracking down a leak they caused.

A dangling SudoG.waitlink can point into a sudogcache list that
has been "forgotten" in order to let the GC collect it, but that
dangling .waitlink keeps the list from being collected.
And then the list holding the SudoG with the dangling waitlink
can find itself in the same situation, and so on. We end up
with lists of lists of unusable SudoGs that are still linked into
the object graph and never collected (given the right mix of
non-trivial selects and non-channel synchronization).

More details in golang.org/issue/9110.

Fixes issue 9110.

LGTM=r
R=r
CC=dvyukov, golang-codereviews, iant, khr
https://codereview.appspot.com/177870043
tag go1.4rc1

LGTM=dsymonds
R=rsc, dsymonds
CC=golang-codereviews
https://codereview.appspot.com/175840043
misc/makerelease: use release-branch.go1.4 for tools and tour

TBR=rsc
R=rsc
CC=golang-codereviews
https://codereview.appspot.com/175870043
debug/goobj: move to cmd/internal/goobj

debug/goobj is not ready to be published but it is
needed for the various binary-reading commands.
Move to cmd/internal/goobj.

(The Go 1.3 release branch deleted it, but that's not
an option anymore due to the command dependencies.
The API is still not vetted nor terribly well designed.)

LGTM=adg, dsymonds
R=adg, dsymonds
CC=golang-codereviews
https://codereview.appspot.com/174250043
misc/nacl: exclude cmd/link from the test zip.

It does not appear to be necessary, and cmd/link does not appear in release branches.

LGTM=rsc
R=adg, rsc
CC=golang-codereviews
https://codereview.appspot.com/176900044
undo CL 176900044 / 561398621ba7

Turns out it *is* needed because the cmd/link tests expect to find their own files.

??? original CL description
misc/nacl: exclude cmd/link from the test zip.

It does not appear to be necessary, and cmd/link does not appear in release branches.

LGTM=rsc
R=adg, rsc
CC=golang-codereviews
https://codereview.appspot.com/176900044
???

TBR=rsc
R=adg, rsc
CC=golang-codereviews
https://codereview.appspot.com/175870045
bump go1.4rc1 tag

Now that the build and builders are fixed, we're good to go.

LGTM=dsymonds
R=rsc, dsymonds
CC=golang-codereviews
https://codereview.appspot.com/177900043