Store dex jar paths in bootclasspath_fragment's apex content info

Previously, the DexBootJarPathForContentModule(module) simply called
directly through to the module to retrieve the dex jar path. This
change changes it so the bootclasspath_fragment retrieves the dex
jars from the module and stores them in the info structure for this
method to retrieve directly.

This makes it easier for the bootclasspath_fragment to stop retrieving
hidden API encoded dex jars from the module and perform the encoding
itself.

Bug: 179354495
Test: m com.android.art com.android.ipsec com.android.os.statsd com.android.conscrypt
      - verify that this does not change the contents of the apex files
Change-Id: Ic79dea080f10f4017f1a75d6d1fb5a3bfe04c2ce