Add testcase for sdf header

ivtest/gold/sdf_header-vvp-stdout.gold

@@ -0,0 +1,10 @@
+ivltests/sdf_header.sdf:2:SDF INFO: Version: 3.0
+ivltests/sdf_header.sdf:3:SDF INFO: Design: test
+ivltests/sdf_header.sdf:4:SDF INFO: Date: Wed Mar 8 12:34:56 2023
+ivltests/sdf_header.sdf:5:SDF INFO: Vendor: No Vendor
+ivltests/sdf_header.sdf:6:SDF INFO: Program: Human
+ivltests/sdf_header.sdf:7:SDF INFO: Program Version: 1.0.0
+ivltests/sdf_header.sdf:9:SDF INFO: Voltage : 5.000000
+ivltests/sdf_header.sdf:10:SDF INFO: Process: best=0.65:nom=1.0:worst=1.8
+ivltests/sdf_header.sdf:11:SDF INFO: Temperature : 25.000000
+ivltests/sdf_header.sdf:12:SDF INFO: Timescale : 1ps

ivtest/ivltests/sdf_header.sdf

@@ -0,0 +1,19 @@
+(DELAYFILE
+  (SDFVERSION "3.0")
+  (DESIGN "test")
+  (DATE "Wed Mar 8 12:34:56 2023")
+  (VENDOR "No Vendor")
+  (PROGRAM "Human")
+  (VERSION "1.0.0")
+  (DIVIDER /)
+  (VOLTAGE 5.5:5.0:4.5)
+  (PROCESS "best=0.65:nom=1.0:worst=1.8")
+  (TEMPERATURE -25.0:25.0:85.0)
+  (TIMESCALE 1 ps)
+  
+  // Do nothing
+  (CELL
+        (CELLTYPE "top")
+        (INSTANCE )
+  )
+)

ivtest/ivltests/sdf_header.v

@@ -0,0 +1,10 @@
+`timescale 1ns/1ps
+
+module top;
+
+  initial begin
+    $sdf_annotate("ivltests/sdf_header.sdf", top);
+  end
+
+endmodule
+

ivtest/regress-vvp.list

@@ -35,3 +35,4 @@ struct_packed_write_read	vvp_tests/struct_packed_write_read.json
 struct_packed_write_read2	vvp_tests/struct_packed_write_read2.json
 sv_foreach9			vvp_tests/sv_foreach9.json
 sv_foreach10			vvp_tests/sv_foreach10.json
+sdf_header			vvp_tests/sdf_header.json

ivtest/vvp_tests/sdf_header.json

@@ -0,0 +1,7 @@
+{
+    "type"   : "normal",
+    "source" : "sdf_header.v",
+    "gold"   : "sdf_header",
+    "iverilog-args" : [ "-gspecify" ],
+    "vvp-args-extended" : [ "-sdf-verbose" ]
+}