Reset LOCAL_PATH so that `mma` can work properly

The value of LOCAL_PATH is overridden by "include $(art_path)/...".
This causes LOCAL_PATH to be empty string when registering modules in
art/Android.mk and this causes MODULES-IN-* logic to not register
properly, hence `mma` not working properly.
Reset the value of LOCAL_PATH back to $(art_path) so that base_rules.mk
can record the module path properly.

Bug: 162918277
Test: m com.android.art
Test: m MODULES-IN-art
Change-Id: I79c5becd0cb81ed85bb5043d5b8150d550657db9
diff --git a/Android.mk b/Android.mk
index e445a14..bee96fe 100644
--- a/Android.mk
+++ b/Android.mk
@@ -275,6 +275,11 @@
 	$(hide) $(call ART_TEST_PREREQ_FINISHED,$@)
 endif
 
+#######################
+# Reset LOCAL_PATH because previous includes may override its value.
+# Keep this after all "include $(art_path)/..." are done, and before any
+# "include $(BUILD_...)".
+LOCAL_PATH := $(art_path)
 
 #######################
 # ART APEX.