Add redeclarations of built-in blocks.

Note: lots of test results changed due to listing the members of a block when printing types.

git-svn-id: https://cvs.khronos.org/svn/repos/ogl/trunk/ecosystem/public/sdk/tools/glslang@23682 e7fa87d3-cd2b-0410-9028-fcbf551c1848

Test/430.vert

@@ -6,3 +6,12 @@ layout(location = 3) uniform vec4 uv4;
 
 layout(location = 2) in   inb1 { vec4 v; } b1;  // ERROR
 layout(location = 2) out outb1 { vec4 v; } b2;  // ERROR
+
+out gl_PerVertex {
+    float gl_ClipDistance[];
+};
+
+void foo()
+{
+    gl_ClipDistance[2] = 3.7;
+}