Shaders: set texture transform in Flat instanced tests when appropriate.

Not when any texture is set, only when texture transformation is
enabled. Because otherwise it won't work when other textures get
added/tested.

src/Magnum/Shaders/Test/FlatGLTest.cpp

@@ -2636,7 +2636,7 @@ template<FlatGL2D::Flag flag> void FlatGLTest::renderInstanced2D() {
                 Matrix3::projection({2.1f, 2.1f})*
                 Matrix3::scaling(Vector2{0.4f}));
 
-        if(data.flags & FlatGL3D::Flag::Textured)
+        if(data.flags & FlatGL3D::Flag::TextureTransformation)
             shader.setTextureMatrix(Matrix3::scaling(
                 #ifndef MAGNUM_TARGET_GLES2
                 /* Slices of the texture array have half the height */
@@ -2688,7 +2688,7 @@ template<FlatGL2D::Flag flag> void FlatGLTest::renderInstanced2D() {
             FlatMaterialUniform{}
                 .setColor(data.flags & FlatGL2D::Flag::Textured ? 0xffffff_rgbf : 0xffff00_rgbf)
         }};
-        if(data.flags & FlatGL3D::Flag::Textured)
+        if(data.flags & FlatGL3D::Flag::TextureTransformation)
             shader.bindTextureTransformationBuffer(textureTransformationUniform);
         shader.bindTransformationProjectionBuffer(transformationProjectionUniform)
             .bindDrawBuffer(drawUniform)
@@ -2904,7 +2904,7 @@ template<FlatGL3D::Flag flag> void FlatGLTest::renderInstanced3D() {
                 Matrix4::translation(Vector3::zAxis(-2.15f))*
                 Matrix4::scaling(Vector3{0.4f}));
 
-        if(data.flags & FlatGL3D::Flag::Textured)
+        if(data.flags & FlatGL3D::Flag::TextureTransformation)
             shader.setTextureMatrix(Matrix3::scaling(
                 #ifndef MAGNUM_TARGET_GLES2
                 /* Slices of the texture array have half the height */
@@ -2957,7 +2957,7 @@ template<FlatGL3D::Flag flag> void FlatGLTest::renderInstanced3D() {
             FlatMaterialUniform{}
                 .setColor(data.flags & FlatGL3D::Flag::Textured ? 0xffffff_rgbf : 0xffff00_rgbf)
         }};
-        if(data.flags & FlatGL3D::Flag::Textured)
+        if(data.flags & FlatGL3D::Flag::TextureTransformation)
             shader.bindTextureTransformationBuffer(textureTransformationUniform);
         shader.bindTransformationProjectionBuffer(transformationProjectionUniform)
             .bindDrawBuffer(drawUniform)