The jitdump header contains a "magic" field that is defined to hold
the value 0x4A695444 as u32 in native endianness. (This allows
consumers of the file to detect the endianness of the platform
where the file was written, and apply it when reading other fields.)
However, current code always writes 0x4A695444 in little-endian
byte order, even on big-endian system. This makes consumers fail
when attempting to read files written on big-endian platforms.
Fixed by always writing the magic in native endianness.
fe10cc9d52