Reland "Switch run_android_wpt to py3"

This reverts commit a8f403b1abe3c4c6ee8ae483cb0fc22a9eb559cd.

Reason for revert: error causing the revert is fixed

Original change's description:
> Revert "Switch run_android_wpt to py3"
>
> This reverts commit 7d961ecace9954f368e56782bffb1ac60fd5b3fc.
>
> Reason for revert: crbug.com/1187233
>
> Original change's description:
> > Switch run_android_wpt to py3
> >
> > Bug: 1186789
> > Change-Id: I3b669e4ecddda1eb24554fb28b4c14730ed80a72
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2747271
> > Reviewed-by: Dirk Pranke <[email protected]>
> > Reviewed-by: Luke Z <[email protected]>
> > Commit-Queue: Weizhong Xia <[email protected]>
> > Cr-Commit-Position: refs/heads/master@{#862070}
>
> Bug: 1186789
> Change-Id: I318622363824ae133d46598868887b1afd414afb
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2754211
> Bot-Commit: Rubber Stamper <[email protected]>
> Commit-Queue: Xiaohan Wang <[email protected]>
> Cr-Commit-Position: refs/heads/master@{#862140}

Bug: 1186789
Change-Id: I573864f66cb50521036f8367bbb5090eaff148df
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2755067
Reviewed-by: Dirk Pranke <[email protected]>
Commit-Queue: Weizhong Xia <[email protected]>
Cr-Commit-Position: refs/heads/master@{#865001}
diff --git a/.vpython3 b/.vpython3
index 26bd1e5..f293af5 100644
--- a/.vpython3
+++ b/.vpython3
@@ -23,6 +23,13 @@
 #   https://chromium.googlesource.com/infra/infra/+/master/doc/users/vpython.md
 
 python_version: "3.8"
+# Used by:
+#   build/android/pylib/local/emulator/avd.py
+#   components/policy/test_support/policy_testserver.py
+wheel: <
+  name: "infra/python/wheels/protobuf-py2_py3"
+  version: "version:3.6.1"
+>
 
 # TODO(https://crbug.com/898348): Add in necessary wheels as Python3 versions
 # become available.
@@ -33,7 +40,7 @@
 
 # Common utilities.
 wheel: <
-  name: "infra/python/wheels/psutil/${platform}_${py_python}_${py_abi}"
+  name: "infra/python/wheels/psutil/${vpython_platform}"
   version: "version:5.7.2"
 >
 wheel: <