public RegisterValue getRegisterValue(Register reg, Address toAddr) {
		return getRegisterValue(reg, Address.NO_ADDRESS, toAddr);
	}
Get the current value of the register at the address.
Note: If trackStartEndState flag is false, then this will return the current value.

@param reg value of register to get
@param toAddr value of register at a location

@return value of register or null
Ghidra/Features/Base/src/main/java/ghidra/program/util/VarnodeContext.java