Narrow down issues with callstack tests

[vringar]

Currently we know the following:

• Running plain FF makes the stackDump API behave as expected.
• Running demo.py (or tests) and the JS Instrument enabled makes the stackDump API behave as expected.
• Running demo.py and no JS leads to the actors not being created in normal windows and only the children being created in privileged windows (DevTool, about:debugging) but even there no callstacks get captured
• Running raw selenium with no JS also leads to the above behaviour

Further suggested exploration:

• Run with a reduced config for non-debugging (prod) setup
• Inject more complex contentscript when running with OpenWPM

Resolution options:

• Find solution on friday
• Programmatically enforce in deployFirefox.py that the callstacks code doesn't run without both HTTP instrument and the JS instrument

[englehardt]

@vringar is this still an issue?

[vringar]

Yes, the error still happens on this version aka our current version.

[englehardt]

We still aren't sure why this is required. For now, we're going to force both instruments to be enabled when the callstack instrument is enabled. We can do this when we validate the browser params config (see #495).