Add info about location of the coverage report

Target 'coverage' outputs now path to the generated coverage report.

Change-Id: I442c0ff002c5d269cf1f573674105691df9caec5

tools/scripts/android_test_rules.xml

@@ -98,6 +98,7 @@
         <delete dir="${instrumentation.absolute.dir}" />
         <delete file="coverage.ec" />
         <delete file="coverage.em" />
+        <echo>Saving the report file in ${basedir}/coverage/coverage.html</echo>
     </target>
 
 </project>