parserTest: delay hooks execution to the point we really need them

parserTest: delay hooks execution to the point we really need them

disabled and filtered out tests were still triggering hooks run. This patch
let us delay hooks running run a little bit until we know we will really need
their execution (i.e. when test is not filtered out and not disabled).

Saving all that unneeded code execution makes running a subset of parser tests
a bit faster when one has many extension enabled.

NOTE: '!!article' sections are still parsed regardless of their usage.
 We would need to add an article/test dependency system to really filter them