No output while running tests when Python extension is also installed

[adityasharad]

Describe the bug
When both the CodeQL extension and the ms-python extension are installed, there is no output or logging when running tests. A while after starting a test, it goes back to the "grey stop symbol" icon (from "blue ellipsis").
(originally observed by @tausbn)

To Reproduce

• Install CodeQL for VS Code 1.4.3 or later.
• Install the VS Code Python extension.
• Open a CodeQL workspace (e.g. github/codeql) and run tests from the Test Explorer view.

Expected behavior

• The tests run, the Test Explorer shows the status, and the Output windows show the logs.

Diagnosis

The VS Code Python extension has a dependency that overrides String.prototype.startsWith for the entire VS Code Node process. This breaks code (in our extension or others) that depends on the 2-argument version of startsWith.
@alexet has filed upstream issues at microsoft/vscode-python#15744 and simonepri/pidtree#13.

Workaround
Affected users may uninstall or disable the VS Code Python extension to work around this problem.