[no sq] Move shaders & remove dead Irrlicht tests (#15006)

* Move irrlicht shaders to correct place

* Remove unused Irrlicht tests

client/shaders/Irrlicht/Solid.vsh

@@ -0,0 +1,38 @@
+#version 100
+
+/* Attributes */
+
+attribute vec3 inVertexPosition;
+attribute vec3 inVertexNormal;
+attribute vec4 inVertexColor;
+attribute vec2 inTexCoord0;
+
+/* Uniforms */
+
+uniform mat4 uWVPMatrix;
+uniform mat4 uWVMatrix;
+uniform mat4 uNMatrix;
+uniform mat4 uTMatrix0;
+
+uniform float uThickness;
+
+/* Varyings */
+
+varying vec2 vTextureCoord0;
+varying vec4 vVertexColor;
+varying float vFogCoord;
+
+void main()
+{
+	gl_Position = uWVPMatrix * vec4(inVertexPosition, 1.0);
+	gl_PointSize = uThickness;
+
+	vec4 TextureCoord0 = vec4(inTexCoord0.x, inTexCoord0.y, 1.0, 1.0);
+	vTextureCoord0 = vec4(uTMatrix0 * TextureCoord0).xy;
+
+	vVertexColor = inVertexColor.bgra;
+
+	vec3 Position = (uWVMatrix * vec4(inVertexPosition, 1.0)).xyz;
+
+	vFogCoord = length(Position);
+}