Measuring tape can flicker

[samreid]

During phetsims/my-solar-system#86 @zepumph and @AgustinVallejo and I observed the measuring tape flickering when the distance measurement was 0:

[AgustinVallejo]

Originally issue in MSS. But with @arouinfar we reproduced it in Projectile Motion.

[arouinfar]

@AgustinVallejo @DianaTavares and I reviewed this issue and determined it is not specific to My Solar System, so it's likely an issue with MeasuringTapeNode.

To reproduce, you must manually drag the tip until it reaches a measurement of 0 units. Then, grab the measuring tape body and drag it around the play area. The flicker is not usually as severe as what is shown in #804 (comment).

This is difficult to reproduce, largely because it is difficult to zero out the measuring tape by hand. Notably, the flicker doesn't seem reproducible if the measuring tape is zeroed out by dragging it to the edge of its bounds. So it's possible the problem arises when the length is very small, not zero.

I would categorize this as a low-severity issue, given the difficulty to reproduce and the general uselessness of measuring a distance of zero. However, I'm going to assign this to the responsible dev of scenery-phet @pixelzoom in case there is a clear/easy solution.

@pixelzoom I completely defer to your judgment here.

[pixelzoom]

Unassigning until someone has a need for this.