Abstract TypeScript methods do not work

[lobodpav]

Describe the bug

When extending an abstract class with an abstract method, the pxt build fails.

To Reproduce

Run pxt build for the program below.

abstract class AbstractPlayer {
    abstract play(): void
}

class Player extends AbstractPlayer {
    play(): void {
        music.play(music.tonePlayable(262, music.beat(BeatFraction.Whole)), music.PlaybackMode.UntilDone)
    }
}

const player = new Player()
player.play()

The compilation fails with

INTERNAL ERROR: Error: Assertion failed
    at Object.assert (/Users/pavel/Git/Microbit/makecode/node_modules/pxt-core/built/pxt.js:98695:27)
    at getVTable (/Users/pavel/Git/Microbit/makecode/node_modules/pxt-core/built/pxt.js:133474:32)
    at emitVTables (/Users/pavel/Git/Microbit/makecode/node_modules/pxt-core/built/pxt.js:134517:21)
    at Object.compileBinary (/Users/pavel/Git/Microbit/makecode/node_modules/pxt-core/built/pxt.js:133162:13)
    at Object.compile (/Users/pavel/Git/Microbit/makecode/node_modules/pxt-core/built/pxt.js:137199:40)
    at /Users/pavel/Git/Microbit/makecode/node_modules/pxt-core/built/pxt.js:165353:21
make: *** [build] Error 20

When changing the AbstractPlayer to

abstract class AbstractPlayer {
    play(): void {}
}

The compilation succeeds and the code works well on micro:bit.

Expected behavior
The compilation should succeed.

Desktop (please complete the following information):

• OS: macOS Sequoia 15.1.1
• target: v7.1.15
• pxt-core v11.3.3