Fix const parameter debug types

Constant qualified parameter types were not being correctly added to
the DebugTypeFunction instruction.

Fix #3095.

gtests/Spv.FromFile.cpp

@@ -858,7 +858,8 @@ INSTANTIATE_TEST_SUITE_P(
         "spv.debuginfo.glsl.comp",
         "spv.debuginfo.glsl.geom",
         "spv.debuginfo.glsl.tesc",
-        "spv.debuginfo.glsl.tese"
+        "spv.debuginfo.glsl.tese",
+        "spv.debuginfo.const_params.glsl.comp"
     })),
     FileNameAsCustomTestSuffix
 );