test_start: allow replacing the default list of tests
test_start: allow replacing the default list of tests

boklm/tbb-testsuite,boklm/tbb-testsuite,gunesacar/tor-browser-bundle-testsuite,boklm/tbb-testsuite,boklm/tbb-testsuite,boklm/tbb-testsuite,gunesacar/tor-browser-bundle-testsuite,gunesacar/tor-browser-bundle-testsuite,gunesacar/tor-browser-bundle-testsuite