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
diff --git a/java/java.go b/java/java.go
index a48b5a3..bfdc7fc 100644
--- a/java/java.go
+++ b/java/java.go
@@ -447,6 +447,7 @@
 	ExportedPlugins() (android.Paths, []string)
 	SrcJarArgs() ([]string, android.Paths)
 	BaseModuleName() string
+	JacocoReportClassesFile() android.Path
 }
 
 type SdkLibraryDependency interface {
@@ -1719,6 +1720,10 @@
 	return proptools.StringDefault(j.deviceProperties.Stem, j.Name())
 }
 
+func (j *Module) JacocoReportClassesFile() android.Path {
+	return j.jacocoReportClassesFile
+}
+
 //
 // Java libraries (.jar file)
 //
@@ -2295,6 +2300,10 @@
 	return proptools.StringDefault(j.properties.Stem, j.ModuleBase.Name())
 }
 
+func (a *Import) JacocoReportClassesFile() android.Path {
+	return nil
+}
+
 func (j *Import) DepsMutator(ctx android.BottomUpMutatorContext) {
 	ctx.AddVariationDependencies(nil, libTag, j.properties.Libs...)
 }