Remove warning that shows on every test run. NFC

[sbc100]

These option is much more discover-able these day because we
have --help which will remind you that you can just to --all-engines.

[kripken]

I found this useful in the past as I'd forget this now and then. But I guess it's not that useful any more.

[sbc100]

I found this useful in the past as I'd forget this now and then. But I guess it's not that useful any more.

These days with have --help which will remind you that you can just to --all-engines

$ ./tests/runner --help
usage: runner.py [-h] [--save-dir] [--no-clean] [--verbose] [--all-engines] [--detect-leaks] [--skip-slow] [--cores CORES]
                 [--rebaseline] [--browser BROWSER]
                 [tests ...]

This is the Emscripten test runner. To run some tests, specify which tests you want, for example tests/runner
asm1.test_hello_world There are many options for which tests to run and how to run them. For details, see
http://kripken.github.io/emscripten-site/docs/getting_started/test-suite.html

positional arguments:
  tests

optional arguments:
  -h, --help         show this help message and exit
  --save-dir         Save the temporary directory used during for each test. Implies --cores=1.
  --no-clean         Do not clean the temporary directory before each test run
  --verbose, -v
  --all-engines
  --detect-leaks
  --skip-slow        Skip tests marked as slow
  --cores CORES      Set the number tests to run in parallel. Defaults to the number of CPU cores.
  --rebaseline       Automatically update test expectations for tests that support it.
  --browser BROWSER  Command to launch web browser in which to run browser tests.