jacoco correctly gathers info from APK-in-APEX

This change fixes a bug that jacoco-report-classes-all.jar does not
include info for APK-in-APEX such as the MediaProvider apk in
com.android.mediaprovider APEX.

Firstly, LOCAL_SOONG_JACOCO_REPORT_CLASSES_JAR is correctly set also for
the APKs included in APEXes. Secondly, the Make modules for the embedded
APKs are now built with soong_app_prebuilt.mk to correctly import the
jacoco file into the Make world.

Bug: 147296855
Test: execute the following command in internal master.
$ choosecombo cf_x86_phone userdebug
$ NINJA_ARGS="-t path out/target/product/vsoc_x86/jacoco-report-classes-all.jar out/target/common/obj/ETC/MediaProvider.com.android.mediaprovider_intermediates/jacoco-report-classes.jar" EMMA_INSTRUMENT=true EMMA_INSTRUMENT_FRAMEWORK=true m
The result shows that there is a path as follows:
out/target/product/vsoc_x86/jacoco-report-classes-all.jar
out/target/product/vsoc_x86/apex/com.android.mediaprovider/priv-app/MediaProvider/MediaProvider.apk
out/target/product/vsoc_x86/obj/ETC/MediaProvider.com.android.mediaprovider_intermediates/package.apk
out/target/common/obj/ETC/MediaProvider.com.android.mediaprovider_intermediates/jacoco-report-classes.jar

Change-Id: I52d11534a34eb35219bfafca4453e75a1b701c0e