build: add option for running all component tests (#18371)
build: add option for running all component tests (#18371)

Adds a `--all` option to the `yarn test` script. This option
can be used to run _all_ component tests in the repository.

Flags like `--no-watch` and `--firefox` can be used in combination with
the new `-all` flag.
crisbeto/material2,mmalerba/material2,Jefiozie/material2,mmalerba/material2,DevVersion/material2,Jefiozie/material2,andrewseguin/material2,DevVersion/material2,angular/components,mmalerba/material2,mmalerba/material2,Jefiozie/material2,Jefiozie/material2,angular/components,mmalerba/material2,josephperrott/material2,DevVersion/material2,Jefiozie/material2,andrewseguin/material2,DevVersion/material2,josephperrott/material2,josephperrott/material2,crisbeto/material2,DevVersion/material2,josephperrott/material2,crisbeto/material2,andrewseguin/material2,crisbeto/material2,angular/components,andrewseguin/material2,angular/components,josephperrott/material2,andrewseguin/material2