tests: Create res-testdata for testdata pickup.

It doesn't change the functionality of the test, but allows easier
conversion to Soong.

Test: Run recovery_component_test on marlin.
Change-Id: Ic7419dc86c6b220531ae44e49ab4657394a5d7fa
diff --git a/tests/Android.mk b/tests/Android.mk
index 3d3e63e..ef64d76 100644
--- a/tests/Android.mk
+++ b/tests/Android.mk
@@ -208,7 +208,7 @@
 
 LOCAL_TEST_DATA := \
     $(call find-test-data-in-subdirs, $(LOCAL_PATH), "*", testdata) \
-    $(call find-test-data-in-subdirs, bootable/recovery, "*_text.png", res-*)
+    $(call find-test-data-in-subdirs, $(LOCAL_PATH), "*_text.png", res-testdata)
 include $(BUILD_NATIVE_TEST)
 
 # Host tests