BUG: Python 3.9 Polyfit sanity test emitted a warning
- [x] I have checked that this issue has not already been reported.

- [x] I have confirmed this bug exists on the latest version of pandas.

- [ ] (optional) I have confirmed this bug exists on the master branch of pandas.

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#### Code Sample, a copy-pastable example

```python
import pandas as pd

```

#### Problem description

When importing pandas using python 3.9.0 I get the following error:

```
python(81328,0x10d755dc0) malloc: can't allocate region
:*** mach_vm_map(size=18446744071827312640, flags: 100) failed (error code=3)
python(81328,0x10d755dc0) malloc: *** set a breakpoint in malloc_error_break to debug
init_dgelsd failed init
Traceback (most recent call last):
  File "/Users/paul/python/test/t.py", line 2, in <module>
    import pandas as pd
  File "/Users/paul/python/test/venv/lib/python3.9/site-packages/pandas/__init__.py", line 11, in <module>
    __import__(dependency)
  File "/Users/paul/python/test/venv/lib/python3.9/site-packages/numpy/__init__.py", line 286, in <module>
    raise RuntimeError(msg)
RuntimeError: Polyfit sanity test emitted a warning, most likely due to using a buggy Accelerate backend. If you compiled yourself, see site.cfg.example for information. Otherwise report this to the vendor that provided NumPy.
RankWarning: Polyfit may be poorly conditioned
```

#### Expected Output

Pandas should import without an error.

#### Output of ``pd.show_versions()``

I am unable to run pd.show_versions() because the program crashes as soon as pandas is imported. I am installing pandas 1.1.3 on a Mac.
