Move split file_contexts to /system and /vendor

Build file_contexts.bin on legacy builds.
Test: Marlin and Bullhead build and boot with no new denials.
Test: Marlin and Bullhead recovery boots with no new denials.
Test: Bullhead boots with file_contexts.bin in /
Test: Marlin boot with /system/etc/selinux/plat_file_contexts and
      /vendor/etc/selinux/nonplat_file_contexts.
Bug: 36002414

Change-Id: Ide8498b3c86234d2f93bb22a7514d132c33067d6

Android.mk

@@ -703,7 +703,7 @@ include $(CLEAR_VARS)
 LOCAL_MODULE := plat_file_contexts
 LOCAL_MODULE_CLASS := ETC
 LOCAL_MODULE_TAGS := optional
-LOCAL_MODULE_PATH := $(TARGET_ROOT_OUT)
+LOCAL_MODULE_PATH := $(TARGET_OUT)/etc/selinux
 
 include $(BUILD_SYSTEM)/base_rules.mk
 
@@ -733,7 +733,7 @@ include $(CLEAR_VARS)
 LOCAL_MODULE := nonplat_file_contexts
 LOCAL_MODULE_CLASS := ETC
 LOCAL_MODULE_TAGS := optional
-LOCAL_MODULE_PATH := $(TARGET_ROOT_OUT)
+LOCAL_MODULE_PATH := $(TARGET_OUT_VENDOR)/etc/selinux
 
 include $(BUILD_SYSTEM)/base_rules.mk