more test coverage and dead code removal

test/basic/fork_join.sv

@@ -0,0 +1,7 @@
+module top;
+    initial
+        fork
+            $display("A");
+            $display("B");
+        join
+endmodule

test/basic/jump.sv

@@ -136,4 +136,13 @@ module top;
         $display("Block F-1");
     end
 
+    initial begin
+        int i;
+        for (i = 0; i < 10; ++i)
+            if (i < 5)
+                $display("Loop F:", i);
+            else
+                break;
+    end
+
 endmodule

test/basic/jump.v

@@ -112,4 +112,10 @@ module top;
         $display("Block F-1");
     end
 
+    initial begin : loop_f
+        integer i;
+        for (i = 0; i < 5; ++i)
+            $display("Loop F:", i);
+    end
+
 endmodule