Don't pass extra arguments to simple event handlers.

When running a simple event handler function call, don't pass more
arguments than the parsed call requested, by passing
plugin_dispatchEvent___ an argument count. (It was tempting to add a
generalized mechanism for allowing reordered and constant arguments,
but that would just be enhancing ES5/3 while we're trying to move away
from it.)

Incidental test suite fix: testExceptionInEventHandler does not
install an onerror handler until it is about to be invoked, so that
unexpected errors from other tests are not interfered with.

Fixes <https://code.google.com/p/google-caja/issues/detail?id=1483>.

@r5386

[kpreid2, 2013-04-29 17:26:53]

ping

[ihab.awad, 2013-04-29 22:22:43]

lgtm

[kpreid2, 2013-04-30 17:52:32]

When running a simple event handler function call, don't pass more
arguments than the parsed call requested, by passing
plugin_dispatchEvent___ an argument count. (It was tempting to add a
generalized mechanism for allowing reordered and constant arguments,
but that would just be enhancing ES5/3 while we're trying to move away
from it.)

Incidental test suite fix: testExceptionInEventHandler does not
install an onerror handler until it is about to be invoked, so that
unexpected errors from other tests are not interfered with.

Fixes <https://code.google.com/p/google-caja/issues/detail?id=1483>.

[kpreid2, 2013-04-30 17:54:44]

New snapshot for the record: I had the test arguments wrong so the 2-arg test
wasn't actually testing the SIMPLE_HANDLER_PATTERN case; this was caught since
it causes a test failure on ES5/3.