unbreak test: test_python_lookup_missing_php_attr
Add a test that shows that BridgeErrors are broken.

For some reason they not catchable as plain Exceptions.
Move a failing test and mark it xfail.
echoing of a python module in PHP is broken.
Remove a test which isn't all that useful.
This test is fixed.
unbreak and move a couple of interpreter level list conversion tests.
Move a couple of test and uncover a potential bug.
This test doesn't make a great deal of sense any more.
Use fixtures in interp level tests.
Move a bunch of tests related to exceptions to the right place.
Merge branch 'tidy_tests' into pypy_bridge