Move StandardPcodeEmulator logic to EmulatorCore

[mnemonikr]

The name StandardPcodeEmulator suggests that an alternative emulator would not use this emulator, which is likely untrue. This logic is core to any emulator. However, additional logic could be performed around this emulator. For example, a wrapper around the core emulator could cache full addition results (including carry) for use in possible follow-up carry operations.

EmulatorCore highlights that this emulator contains the core emulation logic. The StandardPcodeEmulator implementation should simply call this core logic without any other bells and whistles.