[test] Add missing mark_dirty() calls to test cases.

A recent optimisation has added a flag to the image
surface which is used to track whether the surface
is clear or not.  This makes it imperative that clients
call cairo_surface_mark_dirty() if they use cairo to
allocate their pixel buffers and then proceed to
initialize them without telling cairo about it.

test/a1-mask.c

@@ -125,6 +125,7 @@ draw (cairo_t *cr, int dst_width, int dst_height)
 	    dst += stride;
 	}
     }
+    cairo_surface_mark_dirty (surface);
 
     /* Paint background blue */
     cairo_set_source_rgb (cr, 0, 0, 1); /* blue */

test/large-source.c

@@ -62,6 +62,7 @@ draw (cairo_t *cr, int width, int height)
 		data[x] = RED_MASK;
 	    data += stride;
 	}
+        cairo_surface_mark_dirty (surface);
     }
 
     cairo_set_source_rgb (cr, 1, 0, 0); /* red */
@@ -81,6 +82,7 @@ draw (cairo_t *cr, int width, int height)
 		data[x] = GREEN_MASK;
 	    data += stride;
 	}
+        cairo_surface_mark_dirty (surface);
     }
 
     cairo_set_source_rgb (cr, 0, 1, 0); /* green */

test/user-font-mask.c

@@ -126,6 +126,7 @@ test_scaled_font_render_glyph (cairo_scaled_font_t  *scaled_font,
 	*data = CAIRO_BITSWAP8_IF_LITTLE_ENDIAN (byte);
 	data += cairo_image_surface_get_stride (image);
     }
+    cairo_surface_mark_dirty (image);
 
     pattern = cairo_pattern_create_for_surface (image);
     cairo_surface_destroy (image);