Make SpeechRecorder build only on "eng" builds.

This changes the LOCAL_MODULE_TAGS for SpeechRecorder
from "tests" to "eng".

Change-Id: I7071285dd3e1e87bd1dcdda6a96789e6feddeaec
diff --git a/Android.mk b/Android.mk
index 3d2809a..07beaef 100644
--- a/Android.mk
+++ b/Android.mk
@@ -1,7 +1,7 @@
 LOCAL_PATH:= $(call my-dir)
 include $(CLEAR_VARS)
 
-LOCAL_MODULE_TAGS := tests
+LOCAL_MODULE_TAGS := eng
 
 LOCAL_SRC_FILES := $(call all-subdir-java-files) \