Update documentation

Author: jgraham

docs/running-tests/from-local-system.md

@@ -4,8 +4,8 @@ The tests are designed to be run from your local computer.
 
 ## System Setup
 
-Running the tests requires `python`, `pip` and `virtualenv`, as well as updating
-the system `hosts` file.
+Running the tests requires `python` and `pip` as well as updating the
+system `hosts` file.
 
 WPT requires Python 3.7 or higher.
 
@@ -14,12 +14,12 @@ The required setup is different depending on your operating system.
 ### Linux Setup
 
 If not already present, use the system package manager to install `python`,
-`pip` and `virtualenv`.
+and `pip`.
 
-On Debian or Ubuntu:
+On Ubuntu:
 
 ```bash
-sudo apt-get install python python-pip virtualenv
+sudo apt-get install python3 python3-pip python3-venv
 ```
 
 It is important to have a package that provides a `python` binary. On Fedora,
@@ -28,13 +28,12 @@ Ubuntu Focal and later, the package is called `python-is-python3`.
 
 ### macOS Setup
 
-The system-provided Python can be used, while `pip` and `virtualenv` can be
+The system-provided Python can be used, while `pip` can be
 installed for the user only:
 
 ```bash
 python -m ensurepip --user
 export PATH="$PATH:$( python3 -m site --user-base )/bin"
-pip install --user virtualenv
 ```
 
 To make the `PATH` change persistent, add it to your `~/.bash_profile` file or
@@ -50,12 +49,6 @@ installer includes `pip` by default.
 Add `C:\Python39` and `C:\Python39\Scripts` to your `%Path%`
 [environment variable](http://www.computerhope.com/issues/ch000549.htm).
 
-Finally, install `virtualenv`:
-
-```bash
-pip install virtualenv
-```
-
 The standard Windows shell requires that all `wpt` commands are prefixed
 by the Python binary i.e. assuming `python` is on your path the server is
 started using: