[Bug] Unstall condition incorrect when decelerating

[laurensvalk]

Describe the bug
If the motor was unable to track a certain speed, it should not try to catch up when the reference speed is already decreasing.

But it is:

To reproduce

try:
    from pybricks.pupdevices import Motor
except ImportError:
    from pybricks.ev3devices import Motor
from pybricks.tools import wait
from pybricks.parameters import Port
from pybricks import version

print(version)

# Initialize the motor.
motor = Motor(Port.A)

# Allocate the data logs.
DURATION = 7000
motor.control.limits(speed=2000)
motor.log.start(DURATION)
motor.control.log.start(DURATION)

motor.run(2000)
wait(2000)
motor.run(100)
wait(2000)
motor.hold()
wait(2000)


# Transfer data logs.
print("Transferring data...")
motor.log.save("servo.txt")
motor.control.log.save("control.txt")
print("Done")

Originally posted by @laurensvalk in #956 (comment)

[laurensvalk]

This is more generally an issue in drivebases. When driving fast and blocking one wheel, it takes a long time to catch up after release.

[laurensvalk]

I think we can leave this remaining issue as-is.