Shrink the size of a couple of tests (and update reference images).

Shrink linear-gradient and text-pattern test outuput.

The real motivation for this is to hide an annoying difference in the
gradient output that occurs when under the influence of a device
offsets. My opinion is that the gradient output should not change due
to just an integer offset, but we currently don't have a precise
gradient specification, so this minor deviation really isn't relevant.

A better fix for this might have been to make the test suite more
forgiving of tiny differences, (perhaps on a per-test basis), but
another advantage of shrinking these tests is that they now run a lot
faster.

It is true that these tests now also exercise fewer different output
values, but that's not the designed purpose of the tests so I don't
feel bad about losing that characteristic.

test/linear-gradient.c

@@ -47,9 +47,9 @@ static const double rotate_angles[] = { 0, 45, 90 };
 static const int n_stops[] = { 2, 3 };
 #define N_N_STOPS 2
 
-#define UNIT_SIZE 75
-#define UNIT_SIZE 75
-#define PAD 5
+#define UNIT_SIZE 6
+#define UNIT_SIZE 6
+#define PAD 1
 
 #define WIDTH  N_GRADIENT_ANGLES * UNIT_SIZE + (N_GRADIENT_ANGLES + 1) * PAD
 #define HEIGHT N_N_STOPS * N_ROTATE_ANGLES * UNIT_SIZE + (N_N_STOPS * N_ROTATE_ANGLES + 1) * PAD

test/text-pattern.c

@@ -25,8 +25,8 @@
 
 #include "cairo-test.h"
 
-#define IMAGE_WIDTH 100
-#define IMAGE_HEIGHT 100
+#define IMAGE_WIDTH 64
+#define IMAGE_HEIGHT 64
 
 cairo_test_t test = {
     "text-pattern",