Introduce a whitelist for core apps used by system server.

And by default 'speed' compile those apps at build time.

bug:33799337
Test: m -j32

(cherry picked from commit 9af483488a5d0fab89db626fc4d73c993b6d7d2a)

Change-Id: I66f1c675369fccc03b6529c08cb030264d15ba1c
diff --git a/core/product.mk b/core/product.mk
index 3d20168..1e5a30e 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -112,6 +112,7 @@
     PRODUCT_SUPPORTS_VERITY_FEC \
     PRODUCT_OEM_PROPERTIES \
     PRODUCT_SYSTEM_PROPERTY_BLACKLIST \
+    PRODUCT_SYSTEM_SERVER_APPS \
     PRODUCT_SYSTEM_SERVER_JARS \
     PRODUCT_VBOOT_SIGNING_KEY \
     PRODUCT_VBOOT_SIGNING_SUBKEY \