The Angular CLI will continue to call ngcc on all possible packages, even if they
have already been processed by ngcc in a postinstall script.
In a parallel build environment, this was causing ngcc to complain that it was
being run in more than one process at the same time.
This commit moves the check for whether the targeted package has been
processed outside the locked code section, since there is no issue with
multiple ngcc processes from doing this check.
PR Close#34722