bad interaction between radio and jacdac proxy mode

[tballmsft]

See https://makecode.microbit.org/_Eei0YxUotXsy

The program uses the Jacdac extension and sends a radio message. The bad behavior:

1. the second microbit sim starts up and then disappears
2. the first microbit sim goes into jacdac proxy mode, which also causes a reset of micro:bit sim (via control.reset)

Expected behavior:

1. the second micro:bit sim stays up
2. the first micro:bit sim does not go into jacdac proxy mode

[tballmsft]

OK. Here's what's going on (a bad interaction between features):

• the radio message starts the new mbit sim
• the new mbit sim runs a second instance of jacdac, so now there are two mbits on the bus
• the first mbit goes into proxy mode, which also causes reset, so the second mbit goes away

Sigh...

[tballmsft]

I think the solution here is for the Jacdac extension to have a way to specify that only one code (mbit) simulator is allowed. @eanders-ms, @pelikhan, @abchatra - what do you think? This can easily be done via providing a new method in the simulator framework that can be called from Static TypeScript.

[tballmsft]

See

• plumbing to turn off second sim pxt#10263
• control function to turn off creation of second sim pxt-common-packages#1486
• shim for singleSimulator #6009

[tballmsft]

The above changes provide a function to turn off multiple simulators (for the rest of a program execution). See following program

input.onButtonPressed(Button.A, function () {
    radio.sendNumber(0)
})
input.onButtonPressed(Button.B, function () {
	control.reset()
})
input.onButtonPressed(Button.AB, function () {
    control.singleSimulator()
})

[tballmsft]

approved and committed (will need to bump pxt, pxt-common-packages, pxt-microbit): @abchatra

[abchatra]

Done