Automated NDK API coverage used by Mainline modules build integration.

Add gen_ndk_usedby_apex.sh script to generate NDK API list used by Mainlain modules when modules get build.

Test: TARGET_BUILD_APPS=com.android.adbd m dist apps_only

Forrest run: android-build.googleplex.com/builds/forrest/run/L97800000742565481

Change-Id: I39e5aa7c74eff46aba06808642b2bd67ae45ba1e

apex/apex.go

@@ -353,6 +353,9 @@ type apexBundle struct {
 	lintReports android.Paths
 
 	prebuiltFileToDelete string
+
+	// Path of API coverage generate file
+	coverageOutputPath android.ModuleOutPath
 }
 
 // apexFileClass represents a type of file that can be included in APEX.