When targeting ES2015 (as is the default in cli@8), `const` is not
downleveled to `var` and thus declaring `const module` throws an error
due to webpack wrapping the code in a function call with a `module`
argument (even when compiling for the `web` environment).
Related: webpack/webpack#7369
Fixes#30050
PR Close#30058
PR Close#30107
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#29656
George Kalpakas