Clean up TIntermTraverser usage

Remove default parameters from TIntermTraverser.

Also clean up a few dead function declarations in traversers.

TEST=angle_unittests, angle_end2end_tests
BUG=angleproject:1037

Change-Id: I8d126c6c2d5b53e8b14e23e3d102f204a59323b3
Reviewed-on: https://chromium-review.googlesource.com/275184
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Tested-by: Olli Etuaho <oetuaho@nvidia.com>
diff --git a/src/compiler/translator/intermOut.cpp b/src/compiler/translator/intermOut.cpp
index d90aa25..0545839 100644
--- a/src/compiler/translator/intermOut.cpp
+++ b/src/compiler/translator/intermOut.cpp
@@ -27,7 +27,10 @@
 {
   public:
     TOutputTraverser(TInfoSinkBase &i)
-        : sink(i) { }
+        : TIntermTraverser(true, false, false),
+          sink(i)
+    {
+    }
     TInfoSinkBase& sink;
 
   protected: