If we open a `NativeFile` with a `FILE*`, the OpenOptions default to
`eOpenOptionReadOnly`. This is an issue in python scripts if you try to
write to one of the files like `print("Hi",
file=lldb.debugger.GetOutputFileHandle())`.

To address this, we need to specify the access mode whenever we create a
`NativeFile` from a `FILE*`. I also added an assert on the `NativeFile`
that validates the file is opened with the correct access mode and
updated `NativeFile::Read` and `NativeFile::Write` to check the access
mode.

Before these changes:
```
$ lldb -b -O 'script lldb.debugger.GetOutputFileHandle().write("abc")'
(lldb) script lldb.debugger.GetOutputFileHandle().write("abc")
Traceback (most recent call last):
  File "<input>", line 1, in <module>
io.UnsupportedOperation: not writable
```

After:
```
$ lldb -b -O 'script lldb.debugger.GetOutputFileHandle().write("abc")'
(lldb) script lldb.debugger.GetOutputFileHandle().write("abc")
abc3
```

Fixes #122387

StreamFile subclasses Stream (from lldbUtility) and is backed by a File
(from lldbHost). It does not depend on anything from lldbCore or any of its
sibling libraries, so I think it makes sense for this to live in
lldbHost instead.

Differential Revision: https://reviews.llvm.org/D157460