glsl-1.50: Test the minimum maximum of gl_MaxCombinedTextureImageUnits

The new minimum maximum for gl_MaxCombinedTextureImageUnits is 48

Reviewed-by: Matt Turner <mattst88@gmail.com>

tests/spec/glsl-1.50/execution/maximums/gl_MaxCombinedTextureImageUnits.shader_test

@@ -0,0 +1,40 @@
+# [description]
+# Tests for GLSL 1.50 minimum maximums for the builtin constant
+# gl_MaxCombinedTextureImageUnits.
+#
+# The new minimum maximum for gl_MaxCombinedTextureImageUnits is 48;
+# See the GLSL 1.50.09 specification, section 7.4, page 74.
+
+[require]
+GLSL >= 1.50
+
+[vertex shader]
+#version 150
+
+in vec4 vertex;
+
+void main(void)
+{
+	gl_Position = vertex;
+}
+
+[fragment shader]
+#version 150
+void main(void)
+{
+	if (gl_MaxCombinedTextureImageUnits >= 48)
+		gl_FragColor = vec4(0, 1, 0, 0);
+	else
+		gl_FragColor = vec4(1, 0, 0, 0);
+}
+
+[vertex data]
+vertex/float/2
+-1.0 -1.0
+ 1.0 -1.0
+ 1.0  1.0
+-1.0  1.0
+
+[test]
+draw arrays GL_TRIANGLE_FAN 0 4
+probe all rgba 0.0 1.0 0.0 0.0