Fix debug info file and source strings

The file and source text was not being set correctly in the test output.
This change makes the test fixture consistent with the command line
behavior, "-gVS", which was my original intent when I added these tests.

Test/baseResults/spv.debuginfo.const_params.glsl.comp.out

@@ -10,7 +10,7 @@ spv.debuginfo.const_params.glsl.comp
                               MemoryModel Logical GLSL450
                               EntryPoint GLCompute 14  "main"
                               ExecutionMode 14 LocalSize 1 1 1
-               2:             String  ""
+               2:             String  "spv.debuginfo.const_params.glsl.comp"
                8:             String  "uint"
               17:             String  "float"
               35:             String  "function"
@@ -21,6 +21,20 @@ spv.debuginfo.const_params.glsl.comp
 // OpModuleProcessed keep-uncalled
 // OpModuleProcessed entry-point main
 #line 1
+#version 450
+
+void function(
+    const float f,
+    const vec2 f2,
+    const vec3 f3,
+    const vec4 f4)
+{
+}
+
+void main()
+{
+    function(0, vec2(0), vec3(0), vec4(0));
+}
 "
               43:             String  "f"
               49:             String  "f2"