Relative import 'Go to definition' is wrong when the folder matches an upstream folder #2450

Environment data

• VS Code version: 1.26.1
• Extension version (available under the Extensions sidebar): 2018.7.1
• OS and version: macOS High Sierra 10.13.6
• Python version (& distribution if applicable, e.g. Anaconda): 2.7.10
• Type of virtual environment used (N/A | venv | virtualenv | conda | ...): virtualenv
• Relevant/affected Python packages and their versions: N/A

Actual behavior

'Go to definition' looks in the wrong path when the file's folder matches the name of an upstream folder. For example, relative imports for api/whatever/api_test1.py resolves to whatever/ not api/whatever.

Expected behavior

'Go to definition' looks in the current directory for imports.

Steps to reproduce:

Open a new workspace with the following directory structure:

api/
    __init__.py
    whatever/
        __init__.py
        api_test1.py
        api_test2.py
whatever/
    __init__.py
    test1.py
    test2.py
__init__.py

1. Open api_test1.py.
2. Type from .
3. Observe that it autocompletes with test1.py and test2.py instead of the expected api_test2.py.
4. Add a function to api_test2.py and observe that after importing from .api_test2.py import my_func, 'Go to definition' does not work
5. Add a function to test1.py and observe that after importing from .test1.py import my_func, 'Go to definition' opens test1.my_func, which is incorrect

Logs

No errors in Output or Developer Tools consoles