Reads with same glob pattern return same result even if located in different modules/directories

dir1/mod.pkl:
```
foo = read*("foo*")
```

dir2/mod.pkl:
```
foo = read*("foo*") // always returns same result as dir1/mod.foo
```

```
pkl eval dir1/mod.pkl dir2/mod.pkl
```

Fixed by: https://github.com/apple/pkl/pull/449