[lldb] Fix a test assertion after r372192

[lldb] Fix a test assertion after r372192

Summary:
The `CHECK: frame:py: None` seems to have been a typo, causing build bot failures:

```
# CHECK: frame:py: None

         ^

<stdin>:1:1: note: scanning from here

(lldb) command source -s 0 'E:/build_slave/lldb-x64-windows-ninja/build/tools/lldb\lit\lit-lldb-init'

^

<stdin>:23:1: note: possible intended match here

frame:py: No value

^
```

This update fixes the build bots.

--

Reviewers: bkramer

Reviewed By: bkramer

Differential Revision: https://reviews.llvm.org/D67702

llvm-svn: 372221