Consolidate unaligned memory access * The implementations of EXTRACT_{UWORD,WORD,INT} in port.[ch] are removed. Instead, implementations in pike_memory.h are used. * pike_memory.h now uses HANDLES_UNALIGNED_MEMORY_ACCESS to determine when to optimize using raw access, like the functions in port.h used to do, instead of hardcoding for x86_64. * The set of architectures for which HANDLES_UNALIGNED_MEMORY_ACCESS is defined is updated.