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/VariableInfo.cpp b/src/compiler/translator/VariableInfo.cpp
index 808db95..1075f36 100644
--- a/src/compiler/translator/VariableInfo.cpp
+++ b/src/compiler/translator/VariableInfo.cpp
@@ -134,7 +134,8 @@
                                    std::vector<sh::InterfaceBlock> *interfaceBlocks,
                                    ShHashFunction64 hashFunction,
                                    const TSymbolTable &symbolTable)
-    : mAttribs(attribs),
+    : TIntermTraverser(true, false, false),
+      mAttribs(attribs),
       mOutputVariables(outputVariables),
       mUniforms(uniforms),
       mVaryings(varyings),