Ensure that the R8 minification map (ProGuard dictionary) file exists

R8 no longer outputs an empty map file when minification
(obfuscation) is turned off.

Test: m -j PRODUCT-aosp_x86-eng
Change-Id: I3bd3f2900225dca05a972f46a3b882041e17ba49
diff --git a/core/java.mk b/core/java.mk
index d428eb2..6e9b102 100644
--- a/core/java.mk
+++ b/core/java.mk
@@ -489,6 +489,7 @@
 ifdef LOCAL_PROGUARD_ENABLED
   $(built_dex_intermediate): PRIVATE_EXTRA_INPUT_JAR := $(extra_input_jar)
   $(built_dex_intermediate): PRIVATE_PROGUARD_FLAGS := $(legacy_proguard_flags) $(common_proguard_flags) $(LOCAL_PROGUARD_FLAGS)
+  $(built_dex_intermediate): PRIVATE_PROGUARD_DICTIONARY := $(proguard_dictionary)
   $(built_dex_intermediate) : $(full_classes_pre_proguard_jar) $(extra_input_jar) $(my_proguard_sdk_raise) $(common_proguard_flag_files) $(proguard_flag_files) $(legacy_proguard_lib_deps) $(R8_COMPAT_PROGUARD)
 	$(transform-jar-to-dex-r8)
 else # !LOCAL_PROGUARD_ENABLED