feat(fuzzer): Update table scan plan functions to generate multi-join…

… plans (facebookincubator#11940)

Summary:

Generates a cascading multi-join from left to right with table scans as the inputs.

```
[t1, t2, t3, t4]
t1  t2
 \  /
  a   t3
   \  /
     b   t4
      \  /
        c
```

Differential Revision: D67607533