testing/synctest: panic when calling WaitGroup.Add on a package-scope WaitGroup

[neild]

var wg sync.WaitGroup

func TestWaitGroupGlobal(t *testing.T) {
        synctest.Run(func() {
                wg.Go(func() {})
                wg.Wait()
        })
}

fatal error: getOrSetBubbleSpecial on invalid pointer

The problem is that wg isn't in any span, and we can only associate specials with objects in spans.

[gopherbot]

Change https://go.dev/cl/679695 mentions this issue: testing/synctest, runtime: avoid panic when using linker-alloc WG from bubble

[gabyhelp]

Related Code Changes

• testing/synctest, runtime: avoid panic when using linker-alloc WG from bubble

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