Java: Add isImplicitClass table to keep track of compact source files

java/ql/lib/config/semmlecode.dbscheme

@@ -537,6 +537,10 @@ isLocalClassOrInterface(
   int parent: @localtypedeclstmt ref
 );
 
+isImplicitClass(
+  unique int classid: @classorinterface ref
+);
+
 isDefConstr(
   int constructorid: @constructor ref
 );