Refactored PythonSdkFlavor.getVersionStringFromOutput() and added tests

The API was dependent on applying a regexp to version output line by
line which doesn't allow to distinguish between PyPy and PyPy3.
Fix language level detection for PyPy3 (PY-11355)
Get builtins file name by actual language level (PY-11355)
Merge branch 'python-fixes'
simplify scope setting opening
Merge remote-tracking branch 'origin/master'
use ScopeChooserConfigurable.PROJECT_SCOPES
upgrade Guava to v17
EA-56465 - CME: TreeInplaceEditor.hide