fugu: add ro.product.first_api_level for CTS

Bug: 28472442
Change-Id: Ibc686af675d6ac8bf77634807b60f4348d0e4ed6
diff --git a/device.mk b/device.mk
index a52cf2a..f27023c 100644
--- a/device.mk
+++ b/device.mk
@@ -317,3 +317,8 @@
     KeyChain \
     UserDictionaryProvider
 $(call add-product-dex-preopt-module-config,$(FUGU_DONT_DEXPREOPT_MODULES),disable)
+
+# Some CTS tests will be skipped based on what the initial API level that
+# shipped on device was.
+PRODUCT_PROPERTY_OVERRIDES += \
+    ro.product.first_api_level=21