additional interface conversion test coverage

test/basic/interface_array_indirect.sv

@@ -0,0 +1,23 @@
+interface Interface;
+    integer x;
+endinterface
+
+module Single(intf);
+    Interface intf;
+    initial #1 $display("Single %0d", intf.x);
+endmodule
+
+module Group(intfs);
+    parameter WIDTH = 1;
+    Interface intfs [WIDTH];
+    initial $display("Group %0d", WIDTH);
+    for (genvar i = 0; i < WIDTH; ++i)
+        Single s(intfs[i]);
+endmodule
+
+module top;
+    Interface intfs[8]();
+    for (genvar i = 0; i < 8; ++i)
+        initial intfs[i].x = i ** 3;
+    Group #(.WIDTH(8)) g(intfs);
+endmodule