Ensure boot jar modules have been initialized properly for hidden API

Checks to make sure that every module that is part of the platform
bootclasspath has been initialized property for hidden API processing.

Bug: 177892522
Test: verified that the out/soong/hiddenapi/... files are unchanged
      by this change
Change-Id: Ic4368963f2011784b537b8aebf5ef97ea22b2db5