bootstrap: make CJS loader snapshotable

This patch makes the top-level access to runtime states in the
CJS loader lazy, and move the side-effects into a
initializeCJS() function that gets called during pre-execution.
As a result the CJS loader can be included into the built-in
snapshot.

PR-URL: #45849
Backport-PR-URL: #46425
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>