Add test for br_gh1592 and EF var to wire result

Author: caryr

ivtest/ivltests/br_gh1592.v

@@ -0,0 +1,9 @@
+module t;
+  wire [3:0] w;
+  assign w[4:1] = 4'b1010;
+  initial begin
+    #1;
+    if (w !== 4'b010z) $display("FAILED: expected 4'b010z, got '%b'", w);
+    else $display("PASSED");
+  end
+endmodule

ivtest/regress-vlg.list

@@ -379,6 +379,7 @@ br_gh1268a		CE			ivltests
 br_gh1497a		normal,-gspecify	ivltests gold=br_gh1497.gold
 br_gh1497b		normal,-gspecify	ivltests gold=br_gh1497.gold
 br_gh1537		normal			ivltests
+br_gh1592		normal			ivltests
 br_ml20150315		normal			ivltests gold=br_ml_20150315.gold
 br_ml20150321		CE			ivltests
 br_mw20171108		normal			ivltests

ivtest/vvp_tests/struct_packed_write_read.json

@@ -1,5 +1,9 @@
 {
     "type"   : "normal",
     "source" : "struct_packed_write_read.v",
-    "iverilog-args" : [ "-g2009" ]
+    "iverilog-args" : [ "-g2009" ],
+    "vlog95" : {
+        "__comment"     : "variables are cast to wires",
+        "type"          : "EF"
+    }
 }