Don't desugar static java libraries

Static java libraires are designed to be included in another
java library.  If desugar runs on the static java library,
the resulting jar will contain the desugared lambda classes.
When the static jar is included into another java library
and desugar runs again, it desugars the static java library
classes again, producing the same desugared lambda classes
and colliding in the final jar.

Test: m -j ANDROID_COMPILE_WITH_JACK=false
Change-Id: I0508b2cc9c56dbbd4ac0aba44fb99ea2a27715e0
diff --git a/core/java.mk b/core/java.mk
index 1835983..019b055 100644
--- a/core/java.mk
+++ b/core/java.mk
@@ -456,12 +456,14 @@
 my_desugaring :=
 ifndef LOCAL_JACK_ENABLED
 ifeq ($(LOCAL_JAVA_LANGUAGE_VERSION),1.8)
+ifndef LOCAL_IS_STATIC_JAVA_LIBRARY
 my_desugaring := true
 $(full_classes_desugar_jar): PRIVATE_DX_FLAGS := $(LOCAL_DX_FLAGS)
 $(full_classes_desugar_jar): $(full_classes_compiled_jar) $(DESUGAR)
 	$(desugar-classes-jar)
 endif
 endif
+endif
 
 ifndef my_desugaring
 full_classes_desugar_jar := $(full_classes_compiled_jar)