Populate hiddenAPI structure even when not active

The modular hidden API processing needs access to the classesJarPaths
and bootDexJarPath fields of the hiddenAPI structure even if the
modules are not themselves considered to be active participants in the
existing hidden API processing.

This change moves the initialization of those fields to before inactive
modules are ignored.

Bug: 179354495
Test: m art-module-sdk out/soong/hiddenapi/hiddenapi-flags.csv
Change-Id: I06f96d39d0b413295d3e2af50453ebe7e4d3e9c8