Request: Add ability to native instrumentation to report coverage for unused files

[LeoLeal]

Problem: Today, we are unable to get untested files as 0% coverage, because native instrumentation only shows coverage for tested files.

Suggestion: c8 (native v8 coverage reporter) has the ability to add unused files in the coverage report for true code coverage. It makes c8 scan all files recursively from the current directory that matches the patterns in the "include" option, making untested files reported as 0% coverage. This is the --all flag.

It would be nice to be able to pass this as a boolean in the coverageConfig object to turn this --all flag on for c8 (native instrumentation).

[jmcgavin]

+1 This would indeed be very useful in order to get an accurate code coverage report.

[glaubernespoli]

+1. It's just much more accurate to have an idea of how much your whole project is being covered by tests.