Include what these files use

UnitTest.h's EXPECT_ macros all call printf and EXPECT_EQ_MEM calls memcmp, but
it included neither <cstdio> nor <cstring> - it has been relying on whatever the
including file happened to pull in first, and TestMpegCsc was the first not to.
The same shape in sceMpegbase.cpp and sceVideocodec.cpp, which use std::min,
std::move and memcpy without saying where they come from.

Also drop an abs() from TestMpegCsc rather than include <cstdlib> for one
subtraction.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Core/HLE/sceMpegbase.cpp

@@ -20,7 +20,10 @@
 // mpeg.prx drives these directly, so they have to be real for the firmware module to run in place
 // of our sceMpeg HLE.
 
+#include <algorithm>
+#include <cstring>
 #include <map>
+#include <utility>
 #include <vector>
 
 #include "Common/Serialize/Serializer.h"