[PATCH v2 2/6] windowscodecs/tests: Fix tests for CopyBlocks.

[Ziqing Hui]

Using strncmp() to compare pixel data buffer leads to incorrect tests.
Also, we should clear the pixel data buffer before editing and comparing them.

Signed-off-by: Ziqing Hui <zhui(a)codeweavers.com>
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v2: This is a new patch in patch set.
This patch fixes the test failure in previous patch.

 dlls/windowscodecs/tests/ddsformat.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

[Esme Povirk (they/them)]

We want the tests to pass after every patch in the series. You can
probably combine this with patch 1.