SPV: Add support for memory qualifiers.

Test/spv.memoryQualifier.frag

@@ -0,0 +1,38 @@
+#version 450
+
+layout(binding = 0, r32f) uniform coherent image1D      i1D;
+layout(binding = 1, r32f) uniform volatile image2D      i2D;
+layout(binding = 2, r32f) uniform restrict image2DRect  i2DRect;
+layout(binding = 3, r32f) uniform readonly image3D      i3D;
+layout(binding = 3, r32f) uniform writeonly imageCube   iCube;
+
+struct Data
+{
+    float f1;
+    vec2  f2;
+};
+
+coherent buffer Buffer
+{
+    volatile float f1;
+    restrict vec2  f2;
+    readonly vec3  f3;
+    writeonly vec4 f4;
+    int i1;
+    Data data;
+};
+
+void main()
+{
+    vec4 texel = imageLoad(i1D, 1);
+    texel += imageLoad(i2D, ivec2(1));
+    texel += imageLoad(i2DRect, ivec2(1));
+    texel += imageLoad(i3D, ivec3(1));
+    imageStore(iCube, ivec3(1), texel);
+
+    texel[i1] = f1;
+    texel.xy += f2;
+    texel.xyz -= f3;
+    texel.w += data.f1 + data.f2[1];
+    f4 = texel;
+}