enhancement for building app with emma code coverage

* global filter to avoid applying instrumentation on emma classes
* remove local variable information at dex step instead of compile time

Change-Id: If04c27bc717f34816077a98ead9ceb0dbcbb0d2f
diff --git a/core/definitions.mk b/core/definitions.mk
index 5768c6d..3f1dc25 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -1325,7 +1325,8 @@
 
 define transform-classes.jar-to-emma
 $(hide) java -classpath $(EMMA_JAR) emma instr -outmode fullcopy -outfile \
-    $(PRIVATE_EMMA_COVERAGE_FILE) -ip $< -d $(PRIVATE_EMMA_INTERMEDIATES_DIR)
+    $(PRIVATE_EMMA_COVERAGE_FILE) -ip $< -d $(PRIVATE_EMMA_INTERMEDIATES_DIR) \
+    -ix $(PRIVATE_EMMA_COVERAGE_FILTER)
 endef
 
 #TODO: use a smaller -Xmx value for most libraries;