Add regression test for return type of $bits (issue #1163).

ivtest/ivltests/br_gh1163.v

@@ -0,0 +1,24 @@
+`define check(expr) \
+    result = expr; \
+    $display("%b", result); \
+    if (result !== 32'b11111111111111111111111111011111) failed = 1;
+
+module top;
+    integer x;
+    localparam Y = 1'sb1;
+    localparam integer Z = 1'sb1;
+    reg [31:0] result;
+    reg failed = 0;
+    initial begin
+        `check($bits(x) ^ 1'sb1);
+        `check($bits(x) ^ Y);
+        `check($bits(x) ^ Z);
+        `check($signed($bits(x)) ^ 1'sb1);
+        `check($signed($bits(x)) ^ Y);
+        `check($signed($bits(x)) ^ Z);
+         if (failed)
+             $display("FAILED");
+         else
+             $display("PASSED");
+    end
+endmodule

ivtest/regress-vvp.list

@@ -59,6 +59,7 @@ br_gh1143f			vvp_tests/br_gh1143f.json
 br_gh1143g			vvp_tests/br_gh1143g.json
 br_gh1143h			vvp_tests/br_gh1143h.json
 br_gh1155			vvp_tests/br_gh1155.json
+br_gh1163			vvp_tests/br_gh1163.json
 ca_time_real`			vvp_tests/ca_time_real.json
 case1				vvp_tests/case1.json
 case2				vvp_tests/case2.json

ivtest/vvp_tests/br_gh1163.json

@@ -0,0 +1,4 @@
+{
+    "type"   : "normal",
+    "source" : "br_gh1163.v"
+}