use system python (sourcegraph#4072)

* revert back to system python

Author: davejrt

.buildkite/hooks/pre-command

@@ -1,19 +1,7 @@
 #!/usr/bin/env bash
 
 set -eu
-pushd "$(dirname "${BASH_SOURCE[0]}")"/../..
+cd $BUILDKITE_BUILD_CHECKOUT_PATH
 
-TOOL_VERSION_FILES=()
-mapfile -d $'\0' TOOL_VERSION_FILES < <(fd .tool-versions --hidden --absolute-path --print0)
-
-for file in "${TOOL_VERSION_FILES[@]}"; do
-	echo "Installing asdf dependencies as defined in ${file}:"
-	parent=$(dirname "${file}")
-	pushd "${parent}"
-
-	asdf install
-
-	popd
-done
-
-popd
+echo "Installing asdf dependencies as defined in '$BUILDKITE_BUILD_CHECKOUT_PATH/.tool-versions':"
+asdf install

.tool-versions

@@ -5,4 +5,5 @@ pulumi 1.14.1
 fd 7.4.0
 kustomize 4.0.5
 shfmt 3.1.0
-python 3.10.0
+nodejs 12.10.0
+python system