use inf_is_64bit to determine the bitness for IDA_SDK_VERSION>=830

[leommxj]

starting from ida 8.3, ida64.exe can open 32-bit binary and idb file. ida 9.0 has removed ida.exe ph.flag&PR_USE64 return PR_USE64 if we open a 32-bit binary with ida64.exe change to inf_is_64bit from idaapi