tests: fix `filtertraceback.py` to handle contiguous "File" lines It looks like it assumed each `" File"` line would be followed by the code at the referenced line, but that's not true of a few things in `test-hook.t`. That and the fact that there are an odd number of them in that test caused the `self.loader.exec_module(module)` line below to leak through in non-chg tests, when the filter is applied in `test-hook.t`: Traceback (most recent call last): File "C:\Users\Matt\hg\mercurial\hook.py", line 62, in pythonhook obj = __import__(pycompat.sysstr(modname)) File "<frozen importlib._bootstrap>", line 1007, in _find_and_load File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked File "<frozen importlib._bootstrap>", line 680, in _load_unlocked File "C:\Users\Matt\hg\hgdemandimport\demandimportpy3.py", line 52, in exec_module self.loader.exec_module(module) File "$TESTTMP\b\syntaxerror.py", line 1 (foo