[test] Add a set of default tests

[sbc100]

These are the tests that get run if you run just ./test/runner without any args

On my machine these run in about 2m20s:

$ ./test/runner 
Using default tests: jslib other core0
Running 2765 tests
Using 128 parallel test processes
[2765/2765] test_poppler (test_core.core0.test_poppler) ... ok

----------------------------------------------------------------------
Ran 2765 tests in 141.404s

OK (skipped=79)
Total core time: 12129.763s. Wallclock time: 141.404s. Parallelization: 85.78x.