Add --run-disabled and --run-php options.

These parallel the --run-disabled and --run-parsoid options for the
PHP parser tests (see https://gerrit.wikimedia.org/r/50476 ).

At the moment --run-disabled is true by default (so use --run-disabled=no
or --no-run-disabled to turn it off) because many parsoid-specific tests
are still marked with the 'disabled' option.  Once those are all switched
over to using the 'parsoid' options, the default for --run-disabled should
switch to false.

The test-running logic for parsoid's parserTests now matches the
PHP parserTests logic (see tests/testHelpers.inc in the above change set).

Change-Id: Ia2dc633cf49e6daec59662901ed65731efb8a064
Merge "Add --run-disabled and --run-php options."