Permissions XML file for java_sdk_library is mutated for APEX

This change fixes a regression that was introduced with
I597bccbb177b6b6320c3a3edeff467243230d384. With the change, the content
of the permissions XML file for a java_sdk_library was determined before
the java_sdk_library is mutated for an APEX. As a result, the file path
to the implementation jar library was always set to
/system/framework/*.jar regardless of whether the java_sdk_library is
part of an APEX or not.

This change fixes the problem, by creating the permissions XML file via
a new module type. The content of the xml file is determined after the
xml file is mutated for APEXes.

Bug: 149600642
Test: m

Change-Id: Id21f8d8285df49b0b3be1daf0f101f2bc978eeb0