Utilize source maps

[chrisbreiding]

As part of adding code frames for the improved error experience, we need to do the following:

• Enable source maps (unless the user has explicitly disabled them) in the preprocessor
• Gracefully handle the case where the user has disabled source maps
• For errors with a stack:
  • Translate the stack into source code stack
• For command errors:
  • Capture the stack when a command runs
  • If the command fails, use the source maps to trace the command back to the source spec file
  • Pull out the line from the spec file and one two above and below it to display in the error code frame
• For assertion errors:
  • Same as commands but point to and show the assertion
• For reporter UI:
  • Capture the stack when an it runs
  • Display a button in the UI next to the test name that opens the file at that line when clicked

Related: #881

[chrisbreiding]

This won't be complete until #3930 is merged.

[cypress-bot]

The code for this is done in cypress-io/cypress#3930, but has yet to be released.
We'll update this issue and reference the changelog when it's released.

[cypress-bot]

Released in 4.6.0.

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