As of version 10, libraries following the APF will no longer contain
ESM5 output. Hence, tests in ngcc need to be updated as they currently
rely on the release output of `@angular/core`.
Additionally, we'd need to support in ngcc that the `module`
property of entry-points no longer necessarily refers to
`esm5` output, but instead can also target `esm2015`.
We currently achieve this by checking the path the `module`
property points to. We can do this because as per APF, the
folder name is known for the esm2015 output. Long-term for
more coverage, we want to sniff the format by looking for
known ES2015 constructs in the file `module` refers to.
PR Close#36944
The cached file-system was implemented to speed up ngcc
processing, but in reality most files are not accessed many times
and there is no noticeable degradation in speed by removing it.
Benchmarking `ngcc -l debug` for AIO on a local machine
gave a range of 196-236 seconds with the cache and 197-224
seconds without the cache.
Moreover, when running in parallel mode, ngcc has a separate
file cache for each process. This results in excess memory usage.
Notably the master process, which only does analysis of entry-points
holds on to up to 500Mb for AIO when using the cache compared to
only around 30Mb when not using the cache.
Finally, the file-system cache being incorrectly primed with file
contents before being processed has been the cause of a number
of bugs. For example https://github.com/angular/angular-cli/issues/16860#issuecomment-614694269.
PR Close#36687
