[SR-10813] DispatchWorkItem leak on armv7

Issue Description:

We found memory leak with DispatchWorkItem on android-armv7
After a quick research, this leak doesn't reproduce on linux x86_64 and android arm64
So looks like it affects all 32bit platforms
Here is a sample:

import Dispatch

let group = DispatchGroup()
let queue = DispatchQueue.global()

class A {
    deinit {
        print("deinit")
    }
}

func test() {
    let a = A()
    queue.async(group: group, execute: DispatchWorkItem {
        print(a)
    })
}

test()
group.wait()

deinit not called
And without DispatchWorkItem this code also works fine

Start by running the provided DispatchWorkItem sample on android-armv7 and compare its behavior with linux x86_64 and android arm64, where the leak does not reproduce. Trace the libdispatch component involved in DispatchWorkItem and verify the fix by confirming that A's deinit is called after group.wait().