Update logic to add debug modules to art-runtime.

runtime_libart.mk no longer picks the debug APEX for userdebug builds,
so we can't do that here either.

This started to error out because the debug APEX is no longer
installable when it isn't picked by runtime_libart.mk.

Test: m nothing TARGET_BUILD_VARIANT=userdebug
Test: m nothing TARGET_BUILD_VARIANT=eng
Bug: 192006406
Change-Id: I3741d7aa791344d2e87cf4dbcad6be3dd69d1778
diff --git a/Android.mk b/Android.mk
index 09cf3f2..5bddf57 100644
--- a/Android.mk
+++ b/Android.mk
@@ -423,10 +423,10 @@
 #
 # * We will never add them if PRODUCT_ART_TARGET_INCLUDE_DEBUG_BUILD = false.
 # * We will always add them if PRODUCT_ART_TARGET_INCLUDE_DEBUG_BUILD = true.
-# * Otherwise, we will add them by default to userdebug and eng builds.
+# * Otherwise, we will add them by default to eng builds.
 art_target_include_debug_build := $(PRODUCT_ART_TARGET_INCLUDE_DEBUG_BUILD)
 ifneq (false,$(art_target_include_debug_build))
-ifneq (,$(filter userdebug eng,$(TARGET_BUILD_VARIANT)))
+ifneq (,$(filter eng,$(TARGET_BUILD_VARIANT)))
   art_target_include_debug_build := true
 endif
 ifeq (true,$(art_target_include_debug_build))