bpo-30822: Exclude tzdata from regrtest --all (#2775)

When running the test suite using --use=all / -u all, exclude tzdata
since it makes test_datetime too slow (15-20 min on some buildbots)
which then times out on some buildbots.

-u tzdata must now be enabled explicitly, -u tzdata or -u all,tzdata,
to run all test_datetime tests.

Fix also regrtest command line parser to allow passing -u
extralargefile to run test_zipfile64.

Travis CI: remove -tzdata. Replace -u all,-tzdata,-cpu with -u all,-cpu since tzdata is now excluded from -u all.
diff --git a/.travis.yml b/.travis.yml
index 4be6e4c..ba1e417 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -62,7 +62,7 @@
             ./venv/bin/python -m pip install -U coverage
       script:
         # Skip tests that re-run the entire test suite.
-        - ./venv/bin/python -m coverage run --pylib -m test -uall,-cpu,-tzdata -x test_multiprocessing_fork -x test_multiprocessing_forkserver -x test_multiprocessing_spawn
+        - ./venv/bin/python -m coverage run --pylib -m test -uall,-cpu -x test_multiprocessing_fork -x test_multiprocessing_forkserver -x test_multiprocessing_spawn
       after_script:  # Probably should be after_success once test suite updated to run under coverage.py.
         # Make the `coverage` command available to Codecov w/ a version of Python that can parse all source files.
         - source ./venv/bin/activate
@@ -95,7 +95,7 @@
   # Only run on Linux as the check only needs to be run once.
   - if [[ "$TRAVIS_OS_NAME" == "linux" ]]; then ./python Tools/scripts/patchcheck.py --travis $TRAVIS_PULL_REQUEST; fi
   # `-r -w` implicitly provided through `make buildbottest`.
-  - make buildbottest TESTOPTS="-j4 -uall,-cpu,-tzdata"
+  - make buildbottest TESTOPTS="-j4 -uall,-cpu"
 
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