Add cache-compile-job to features.json

Add `cache-compile-job` to toolchain feature JSON file so build
system/swift driver can query.

Author: cachemeifyoucan

lib/Option/features.json

@@ -38,6 +38,9 @@
     },
     {
       "name": "ld-path-driver-option"
+    },
+    {
+      "name": "cache-compile-job"
     }
   ]
 }