Bug 1876501 - Use taskcluster-built python for all toolchain/misc r=ahochheiden

Except the task required to build python itself, otherwise we have a
loop, and taskcluster cannot handle that.

Differential Revision: https://phabricator.services.mozilla.com/D199617

taskcluster/kinds/toolchain/misc.yml

@@ -6,6 +6,7 @@ task-defaults:
     worker-type: b-linux-gcp
     worker:
         max-run-time: 1800
+    use-python: default
 
 linux64-binutils-2.31.1:
     description: "Binutils toolchain build"
@@ -208,6 +209,7 @@ macosx64-xz:
         symbol: TM(xz)
     worker:
         max-run-time: 30000
+    use-python: system  # dependency of taskcluster python
     run:
         script: build-xz.sh
         toolchain-artifact: public/build/xz.tar.zst