Starlark: better reflection cache in CallUtils

Replace Guava cache with ConcurrentHashMap. Guava cache is quite
expensive for quick operations.

Dummy native call heavy benchmark:

```
def test():
    for i in range(10):
        print(i)
        for j in range(1000):
            for k in range(200):
                list()
                list()
                list()
                list()
                list()
                list()
                list()
                list()
                list()
                list()
                list()
                list()
test()
```

```
$ time bazel-bin/src/main/java/net/starlark/java/cmd/Starlark ./c.star
```

Before: 3.5s
After: 2.9s

Closes #11681.

PiperOrigin-RevId: 320937877