Covered ranges were not merged and thus it appeared that some lines
might be uncovered. To fix this I used "v8-coverage" that takes care
of merging the ranges properly. With this change, coverage collected
from a file by multiple entrypoints is now correctly calculated.
I ended up forking https://github.com/demurgos/v8-coverage and adding
"cli/tools/coverage/merge.rs" and "cli/tools/coverage/range_tree.rs".
This commit changes "deno coverage" command not to type check.
Instead of relying on infrastructure for module loading in "deno run";
the code now directly reaches into cache for original and transpiled
sources. In case sources are not available the error is returned to the
user, suggesting to first run "deno test --coverage" command.
