adb: restore adb/adb.exe in the list of artifacts.

Test: m dist
Change-Id: Iba44a03e79af9242bfe36efb736496f8db720ebf

adb/Android.mk

+LOCAL_PATH := $(call my-dir)
+
+# Archive adb, adb.exe.
+$(call dist-for-goals,dist_files sdk win_sdk,$(HOST_OUT_EXECUTABLES)/adb)
+
+ifdef HOST_CROSS_OS
+$(call dist-for-goals,dist_files sdk win_sdk,$(ALL_MODULES.host_cross_adb.BUILT))
+endif