Add extra dependency from apex to bootclasspath fragments to modules

An extra dependency from apex modules to their bootclasspath fragments
and from bootclasspath fragments to their contents is necessary, as the
existing one with bcpfTag return false from ReplaceSourceWithPrebuilt
to never rewrite the dependency to the prebuilt fragment, and we'll
need a dependency to the prebuilt fragment in the next CL.

Bug: 372543712
Test: all soong tests pass
Change-Id: I87ff3afa0d5c90936664dd493654f1d64230b8a9