Update GPU testing documentation

Makes some minor updates to the GPU testing documentation to clarify
some confusion that a first-time user recently encountered:

* Updates the webgl_conformance suite to correctly reflect that there is
  now a webgl1_conformance and webgl2_conformance suite.
* Makes it clearer that `vpython3` needs to be manually included when
  running the script on Windows.

Change-Id: Iefbef22db9234f0d7d3413433366a9e186fc7eee
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4443043
Reviewed-by: Yuly Novikov <[email protected]>
Auto-Submit: Brian Sheedy <[email protected]>
Commit-Queue: Yuly Novikov <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1132443}
diff --git a/docs/gpu/gpu_testing.md b/docs/gpu/gpu_testing.md
index 2e8799c..32c46f4b 100644
--- a/docs/gpu/gpu_testing.md
+++ b/docs/gpu/gpu_testing.md
@@ -190,7 +190,8 @@
 in `src/content/test/gpu/gpu_tests/`. For example:
 
 *   `run_gpu_integration_test.py context_lost --browser=release`
-*   `run_gpu_integration_test.py webgl_conformance --browser=release --webgl-conformance-version=1.0.2`
+*   `run_gpu_integration_test.py webgl1_conformance --browser=release`
+*   `run_gpu_integration_test.py webgl2_conformance --browser=release --webgl-conformance-version=2.0.1`
 *   `run_gpu_integration_test.py maps --browser=release`
 *   `run_gpu_integration_test.py screenshot_sync --browser=release`
 *   `run_gpu_integration_test.py trace_test --browser=release`
@@ -221,13 +222,14 @@
 
 **Note:** The tests require some third-party Python packages. Obtaining these
 packages is handled automatically by `vpython3`, and the script's shebang should
-use vpython if running the script directly. If you're used to invoking `python3`
-to run a script, simply use `vpython3` instead, e.g.
-`vpython3 run_gpu_integration_test.py ...`.
+use vpython if running the script directly. Since shebangs are not used on
+Windows, you will need to manually specify the executable if you are on a
+Windows machine. If you're used to invoking `python3` to run a script, simply
+use `vpython3` instead, e.g. `vpython3 run_gpu_integration_test.py ...`.
 
 You can run a subset of tests with this harness:
 
-*   `run_gpu_integration_test.py webgl_conformance --browser=release
+*   `run_gpu_integration_test.py webgl1_conformance --browser=release
     --test-filter=conformance_attribs`
 
 The exact command used to invoke the test on the bots can be found in one of