This halves access to attributes such as methods or _sunder_ name

Benchmarked using:
```
from enum import Enum

class Color(Enum):
    RED = "Red"
    BLUE = "Blue"
    GREEN = "Green"

def f():
    for _ in range(1000):
        Color.RED
        Color.BLUE
        Color.GREEN

def g():
    for _ in range(1000):
        Color.RED._name_
        Color.BLUE._name_
        Color.GREEN._name_

import timeit
print(timeit.timeit('f()', number=10000, globals=globals()))
print(timeit.timeit('g()', number=10000, globals=globals()))
```

As of today morning:
```
6da988a λ ./python.exe bm_enum.py
1.499613167019561
1.5516562079428695
```

As of the latest enum change python#94913:
```
c20186c λ ./python.exe bm_enum.py
1.4998537090141326
16.095267291995697
```

As of this PR:
```
pythongh-93910-micro λ ./python.exe bm_enum.py
1.4983433339511976
8.81327024998609
```