We shouldn't throw under FLAG_debug_code, rather abort.

We shouldn't throw under FLAG_debug_code, rather abort.

Throwing under FLAG_debug_code confuses the rest of our infrastructure
which expects a safe point at the site of call into the runtime
for throw. We were doing that to make a clusterfuzz test happy, but
the better solution is to assert/abort under debug_code, and prevent
clusterfuzz from fuzzing on internal APIs that crash on incorrect
values.

We'll need to alter the fuzzer to turn off fuzzing for:

string-natives.js
lithium/SeqStringSetChar.js
regress/regress-seqstrsetchar-ex3.js
regress/regress-seqstrsetchar-ex1.js
regress/regress-crbug-320922.js

So as to prevent the fuzzer from running
%_OneByteSeqStringSetChar() and
%_TwoByteSeqStringSetChar().

BUG=
R=hpayer@chromium.org, machenbach@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=18878

[mvstanton, 2014-01-27 15:14:40]

Hi Hannes, hi Michael,
Here is the issue we discussed.
Thanks,
--Michael

[Hannes Payer (out of office), 2014-01-27 15:58:42]

LGTM

[Michael Achenbach, 2014-01-28 11:42:58]

LGTM, CF is ready.

[mvstanton, 2014-01-28 11:53:24]

Committed patchset #2 manually as r18878 (presubmit successful).