Fix crash in MSVC Debug build when use SSE 4.1 due uninitialized variables.

[Aleksoid1978]

No description provided.

[Aleksoid1978]

Shouldn't we always initialize __m256i and __m128i variables, and not just in Debug mode?
There, in the code, reading from an uninitialized variable occurs.

Using an uninitialized variable - this is a potential UB.

[adamjw24]

If you look into the code, you can see all the variables are initialized properly, no UB will happen. At least not with the block sizes possible in VVC. For Debug Mode I know MSVC is oversensitive sometimes.