ecma_transforms:
- implement es2015::instanceof
- implement es2015::typeof_symbol
- implement inline_globals pass
ecma_parser:
- `PResult<T>` is now `Result<T, ()>` and `Err(())` means that an error is emitted.
- add docs
* constructor codegen
* Update string_cache to 0.7
* make swc_common not depend on sourcemap
* Remove unused dependencies
* update either to 1.5.0
* update rustc-ap crates to 297
* remove unused dependency (fnv)