Previously we had to share code between upgrade/dynamic and upgrade/static
by symlinking the `src` folder, which allowed both packages to access
the upgrade/common files.
These symlinks are always problematic on Windows, where we had to run
a script to re-link them, and restore them.
This change uses Bazel packages to share the `upgrade/common` code,
which avoids the need for symlinking the `src` folder.
Also, the Windows specific scripts that fixup the symlinks have also
been removed as there is no more need for them.
PR Close#29466
--watchfs is causing the build to be flaky on Windows because Bazel
doesn't have proper support for watchfs on Windows, but it doesn't seem
to bring much performance on Linux, either.
Fixes: https://github.com/angular/angular/issues/29541
PR Close#29635