public int getInstructionStackDepthChange(Instruction instr) {
		return getInstructionStackDepthChange(instr, null, 0);
	}
Inspect the instruction and return how it affects the stack depth. If the
depth cannot be determined, then return that the stack depth change is
unknown.

@param instr
           instruction to analyze

@return int change to stack depth if it can be determined,
        Function.UNKNOWN_STACK_DEPTH_CHANGE otherwise.
Ghidra/Features/Base/src/main/java/ghidra/app/cmd/function/CallDepthChangeInfo.java