Add legacy-android-test target containing android.test classes

In preparation for removing junit classes from the Android API
the legacy-test target will be removed from the
TARGET_DEFAULT_JAVA_LIBRARIES. This change adds a
legacy-android-test target, containing only the android.test
classes, for use by any targets that depend on those classes.

Bug: 30188076
Test: make checkbuild
Change-Id: Ifc0a9a23d4ac3c78428bb9dde38e547e6978ba7e
diff --git a/legacy-test/Android.mk b/legacy-test/Android.mk
index 5e72a0d..0a814f3 100644
--- a/legacy-test/Android.mk
+++ b/legacy-test/Android.mk
@@ -18,7 +18,8 @@
 
 # Build the legacy-test library
 # =============================
-# This contains the junit.framework classes that were in Android API level 25.
+# This contains the junit.framework and android.test classes that were in
+# Android API level 25.
 include $(CLEAR_VARS)
 
 LOCAL_SRC_FILES := $(call all-java-files-under, src)
@@ -28,6 +29,18 @@
 
 include $(BUILD_JAVA_LIBRARY)
 
+# Build the legacy-android-test library
+# =============================
+# This contains the android.test classes that were in Android API level 25.
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := $(call all-java-files-under, src/android)
+LOCAL_MODULE := legacy-android-test
+LOCAL_NO_STANDARD_LIBRARIES := true
+LOCAL_JAVA_LIBRARIES := core-oj core-libart framework junit
+
+include $(BUILD_STATIC_JAVA_LIBRARY)
+
 ifeq ($(HOST_OS),linux)
 # Build the legacy-performance-test-hostdex library
 # =================================================