Add a Tag field to dist to dist a tagged output

Make java_library support this mode of output, to allow
callers to dist the classes.jar file rather than the dexed
jar file.

Bug: 152618077
Test: followup CL
Change-Id: I5ba6949833a0fbb95376142aec5096ff5f084c00
Merged-In: I5ba6949833a0fbb95376142aec5096ff5f084c00
(cherry picked from commit 1e65f94a4b2cc7dea1896937c2068b87c899c465)
diff --git a/java/androidmk.go b/java/androidmk.go
index ee2437a..136bb36 100644
--- a/java/androidmk.go
+++ b/java/androidmk.go
@@ -72,6 +72,7 @@
 	if !hideFromMake {
 		mainEntries = android.AndroidMkEntries{
 			Class:      "JAVA_LIBRARIES",
+			DistFile:   android.OptionalPathForPath(library.distFile),
 			OutputFile: android.OptionalPathForPath(library.outputFile),
 			Include:    "$(BUILD_SYSTEM)/soong_java_prebuilt.mk",
 			ExtraEntries: []android.AndroidMkExtraEntriesFunc{