exec-all.h: increase MAX_OP_PER_INSTR to 96 from 64

The x86_64 ror instruction on a 32-bit host can generate up to 77 TCG
ops. Some more space should be left for opc that are added at the end
of the translation.

Thanks to Laurent Desnogues for the debugging help.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>