Ensure that CodeAst nodes always start at (0, 0).
Previously the start was that of the first child node.
From CPython 3.8.2, the range of an attribute access
includes the leading parenthesis, and thus starts before
The range of kdev-python's Attribute node represents only the range of
blah, and is calculated in an awkward way.
When an attribute access of a parenthesized expression appeared at the
start of a file, the start of the attribute range from CPython was
before that of the CodeAst node (based on the start of
resulting in an incorrect range being calculated.
This case is very unusual in real code, but fixes the tests. ;-)