Memory leak in SSR

[pearofducks]

Version

3.0.0

Reproduction link

https://github.com/pearofducks/vue-ssr-memory-leak

Steps to reproduce

1. Run yarn in both the rc5 and gm dirs
2. Run node test.js in the rc5 dir - note the two ENDING numbers reported
3. Run node test.js in the gm dir - note the two ENDING numbers reported

What is expected?

Some memory should be reclaimed by the gm run after the SLEEPING step

What is actually happening?

No memory is reclaimed

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This is my best approximation of what we're seeing in a much more complicated SSR environment. When we change dependencies (and only the Vue-specific dependencies) from the 3.0.0-rc.5 release to 3.0.0 we see a very clear memory leak.

[posva]

Thanks for the boiled down repro!