Apparently, breakpoints and watchpoints are practically disabled if
run with OPcache JIT under Windows, so we mark the affected tests as
xfail in that case for the time being.
Also adds an --asan flag to run-tests.php to setup all the necessary
environment variables. Some tests are marked as skipped because they
are incompatible with asan or too slow.
I'm basing this on the DEBUG_ZTS build, which seems to give us the
most mileage.
This mainly involves a separate abstraction layer for elements (e.g. $a->b) and watchpoints (on pointer of the Bucket for example).
Also better comparison handling (value backup vs. page dumps).
It is not yet finished (there are sometimes false positives announced and names not yet perfect), but the functionality is working and not crashing as far as I have tested.
Future scope is also relative watchpoints, e.g. "w $this->val expression()" which does not have the symbol tables as basis, but the value (in this example: return value of expression()) as basis.
