Add instrumentation to track down a crasher

Add instrumentation to track down a crasher

LoadICs must always return a JS-accessible value (nothing internal).
Dictionary property keys are guaranteed to be unique names.

BUG=chromium:527994
LOG=n

Committed: https://crrev.com/071d03a431237ad31a11533b572ff647801ac82c
Cr-Commit-Position: refs/heads/master@{#30683}

[Jakob Kummerow, 2015-09-10 12:46:51]

jkummerow@chromium.org changed reviewers:
+ mvstanton@chromium.org

[Jakob Kummerow, 2015-09-10 12:46:52]

As discussed.

It would be nice to push the receiver (and its map, and its properties backing
store) onto the stack before crashing in case of failure, but the
LoadIC::ReceiverRegister must be considered clobbered after the IC returns, and
saving it on the stack would likely upset the deoptimizer, so for now I'll hope
that minidumps will contain enough information even without such tricks.

I've verified that this doesn't immediately run into failures. Let's run it on
the Dev channel.

I'm not planning to do any additional platform ports, x64 should provide enough
coverage.

[mvstanton, 2015-09-10 13:04:36]

lgtm

[Jakob Kummerow, 2015-09-10 13:41:06]

The CQ bit was checked by jkummerow@chromium.org

[Jakob Kummerow, 2015-09-10 13:41:06]

The patchset sent to the CQ was uploaded after l-g-t-m from
mvstanton@chromium.org
Link to the patchset: https://codereview.chromium.org/1334673003/#ps20001
(title: "save receiver and push it before crashing")

[commit-bot: I haz the power, 2015-09-10 13:41:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1334673003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1334673003/20001

[commit-bot: I haz the power, 2015-09-10 14:07:45]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-09-10 14:08:11]

Patchset 2 (id:??) landed as
https://crrev.com/071d03a431237ad31a11533b572ff647801ac82c
Cr-Commit-Position: refs/heads/master@{#30683}