[llvm] [lit] Implement builtin umask (PR #94621)

[Petr Hosek via llvm-commits]

================
@@ -87,10 +87,11 @@ class ShellEnvironment(object):
     we maintain a dir stack for pushd/popd.
     """
 
-    def __init__(self, cwd, env):
+    def __init__(self, cwd, env, umask=-1):
         self.cwd = cwd
         self.env = dict(env)
         self.dirStack = []
+        self.umask = umask
----------------
petrhosek wrote:

This is just a nit but I'd reorder these two fields to match the order of arguments.

```suggestion
        self.umask = umask
        self.dirStack = []
```

https://github.com/llvm/llvm-project/pull/94621