Web: Turn off includes, independent preprocessing path, fine tune all.

Saved about 21K, size down to 380K of MSVC x86 code.
Fixed one bug that needs to be looked at on the master branch:
The test for needing a Vulkan binding has a bug in it, "!layoutAttachment"
which does not mean "no layoutAttachment", because that is non-zero.
This is why some test and test results changed.

glslang/MachineIndependent/linkValidate.cpp

@@ -89,8 +89,6 @@ void TIntermediate::merge(TInfoSink& infoSink, TIntermediate& unit)
 #endif
 }
 
-#ifndef GLSLANG_WEB
-
 void TIntermediate::mergeCallGraphs(TInfoSink& infoSink, TIntermediate& unit)
 {
     if (unit.getNumEntryPoints() > 0) {
@@ -106,6 +104,8 @@ void TIntermediate::mergeCallGraphs(TInfoSink& infoSink, TIntermediate& unit)
     callGraph.insert(callGraph.end(), unit.callGraph.begin(), unit.callGraph.end());
 }
 
+#ifndef GLSLANG_WEB
+
 #define MERGE_MAX(member) member = std::max(member, unit.member)
 #define MERGE_TRUE(member) if (unit.member) member = unit.member;
 
@@ -307,6 +307,8 @@ void TIntermediate::mergeTrees(TInfoSink& infoSink, TIntermediate& unit)
     ioAccessed.insert(unit.ioAccessed.begin(), unit.ioAccessed.end());
 }
 
+#endif
+
 // Traverser that seeds an ID map with all built-ins, and tracks the
 // maximum ID used.
 // (It would be nice to put this in a function, but that causes warnings
@@ -485,7 +487,6 @@ void TIntermediate::mergeImplicitArraySizes(TType& type, const TType& unitType)
     for (int i = 0; i < (int)type.getStruct()->size(); ++i)
         mergeImplicitArraySizes(*(*type.getStruct())[i].type, *(*unitType.getStruct())[i].type);
 }
-#endif // not GLSLANG_WEB
 
 //
 // Compare two global objects from two compilation units and see if they match
@@ -1258,6 +1259,7 @@ int TIntermediate::computeTypeUniformLocationSize(const TType& type)
 }
 
 #ifndef GLSLANG_WEB
+
 // Accumulate xfb buffer ranges and check for collisions as the accumulation is done.
 //
 // Returns < 0 if no collision, >= 0 if collision and the value returned is a colliding value.
@@ -1374,7 +1376,8 @@ unsigned int TIntermediate::computeTypeXfbSize(const TType& type, bool& contains
         return 4 * numComponents;
     }
 }
-#endif // not GLSLANG_WEB
+
+#endif
 
 const int baseAlignmentVec4Std140 = 16;