Added several quote tests.
* Added tests by different quote sequence signatures -- primarily
to stress parsoid in different situations and figure out/document
where Parsoid needs to conform with PHP parser output and where
it is acceptable to diverge.
* Some of these tests can likely be purged since they don't test
anything beyond what is already tested elsewhere, but I haven't
investigated that yet. But, there is probably no harm in a few
duplicated tests.
Change-Id: Id2c7b3ea4dac5f9e8f9b042b439061bf9faea9f2