These methods are confusing because the arguments are backwards. I feel
like they should have never been added to `Option<T>` and that clippy
should suggest rewriting to
`map(...).unwrap_or(...)`/`map(...).unwrap_or_else(|| ...)`
https://github.com/rust-lang/rfcs/issues/1025
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".
