[lldb][gui] move TestGuiBasicDebug.py to lldb/test and update it
Between the time it was created and it was pushed upstream,
99451b4453688a94c6014cac233d371ab4cc342d has moved the existing
gui gui tests to lldb/test, so move this one too.
And update it to contain TestGuiBasic.py changes since the time
when it was based on that test.
Differential Revision: https://reviews.llvm.org/D85106