WIP: SPV Remapper: add remapper test framework

Test/remap.switch.everything.frag

@@ -0,0 +1,16 @@
+#version 450
+
+precision highp float;
+
+layout(location = 0) out mediump vec4 FragColor;
+layout(location = 0) in vec4 in0;
+
+void main()
+{
+    switch(int(in0.w)) {
+    case 0: FragColor = vec4(in0.x + 0); break;
+    case 1: FragColor = vec4(in0.y + 1); break;
+    case 2: FragColor = vec4(in0.z + 2); break;
+    default: FragColor = vec4(-1);
+    }
+}