testautomation_surface: Really make width * bpp overflow

A surface of width (0x7fff'ffff) / 2 = 0x3fff'ffff is not quite large
enough to make the pitch overflow in the way we wanted to test here:
with a 32-bit format, that makes each row 0xffff'fffc bytes, which
(just) fits in a 32-bit unsigned size_t. Increasing it to 0x4000'0000
pixels per row is enough to trigger the overflow we intended to test.

In SDL 2, this test bug was hidden by the fact that allocating
0xffff'fffc bytes on a 32-bit platform is very likely to fail, and SDL 2
reported both "malloc() failed" and "this amount of memory is too large
for a size_t" with the same error code.

Signed-off-by: Simon McVittie <smcv@collabora.com>

test/testautomation_surface.c

@@ -772,7 +772,8 @@ int surface_testOverflow(void *arg)
         SDLTest_AssertCheck(surface == NULL, "Should detect overflow in width + alignment");
         SDLTest_AssertCheck(SDL_strcmp(SDL_GetError(), expectedError) == 0,
                             "Expected \"%s\", got \"%s\"", expectedError, SDL_GetError());
-        surface = SDL_CreateRGBSurfaceWithFormat(0, SDL_MAX_SINT32 / 2, 1, 32, SDL_PIXELFORMAT_ARGB8888);
+        /* 0x4000'0000 * 4bpp = 0x1'0000'0000 which (just) overflows */
+        surface = SDL_CreateRGBSurfaceWithFormat(0, 0x40000000, 1, 32, SDL_PIXELFORMAT_ARGB8888);
         SDLTest_AssertCheck(surface == NULL, "Should detect overflow in width * bytes per pixel");
         SDLTest_AssertCheck(SDL_strcmp(SDL_GetError(), expectedError) == 0,
                             "Expected \"%s\", got \"%s\"", expectedError, SDL_GetError());