Increase the chance of printing a useful error when bootstrapping fails

Increase the chance of printing a useful error when bootstrapping fails

Two changes:
  - In ReportBootstrappingException, if all we have is a string, it seems
    better to print that than nothing.
  - In Factory::NewError, there's no use trying to call into the builtins if
    compilation of the builtins is causing the exception (this currently
    results in a cryptic segfault if we trigger, say, a ReferenceError when
    executing builtins script during bootstrapping).

Committed: https://crrev.com/0be9c69e6ce765a3ed2c2a385b807b5b5e4221dd
Cr-Commit-Position: refs/heads/master@{#28912}

[adamk, 2015-06-02 19:43:28]

adamk@chromium.org changed reviewers:
+ yangguo@chromium.org

[Yang, 2015-06-08 08:55:08]

On 2015/06/02 19:43:29, adamk wrote:

LGTM!

[adamk, 2015-06-10 16:39:05]

The CQ bit was checked by adamk@chromium.org

[commit-bot: I haz the power, 2015-06-10 16:39:17]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1158013003/20001

[commit-bot: I haz the power, 2015-06-10 17:42:07]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-06-10 17:42:26]

Patchset 2 (id:??) landed as
https://crrev.com/0be9c69e6ce765a3ed2c2a385b807b5b5e4221dd
Cr-Commit-Position: refs/heads/master@{#28912}