fasttest compat with old script

docker/test/fasttest/run.sh

@@ -284,8 +284,14 @@ case "$stage" in
     # Pass control to the script from cloned sources, unless asked otherwise.
     if ! [ -v FASTTEST_LOCAL_SCRIPT ]
     then
-        # 'run' is deprecated, used for compatibility with old scripts.
+        # 'run' stage is deprecated, used for compatibility with old scripts.
         # Replace with 'clone_submodules' after Nov 1, 2020.
+        # cd and CLICKHOUSE_DIR are also a setup for old scripts, remove as well.
+        # In modern script we undo it by changing back into workspace dir right
+        # away, see below. Remove that as well.
+        cd "$FASTTEST_SOURCE"
+        CLICKHOUSE_DIR=$(pwd)
+        export CLICKHOUSE_DIR
         stage=run "$FASTTEST_SOURCE/docker/test/fasttest/run.sh"
         exit $?
     fi
@@ -295,6 +301,10 @@ case "$stage" in
     # after cloning root, starting with cloning submodules.
     ;&
 "clone_submodules")
+    # Recover after being called from the old script that changes into source directory.
+    # See the compatibility hacks in `clone_root` stage above. Remove at the same time,
+    # after Nov 1, 2020.
+    cd "$FASTTEST_WORKSPACE"
     clone_submodules | ts '%Y-%m-%d %H:%M:%S' | tee "$FASTTEST_OUTPUT/submodule_log.txt"
     ;&
 "run_cmake")