pycodestyle: Test E402 (imports at top of file)

After the sys.path cleanups and the removal of pkg/machines/, there are
no more cases of E402.  Remove our exception for it.

Author: allisonkarlitskaya

tools/test-static-code

@@ -128,8 +128,7 @@ else
     PYFILES="$(git grep -lI '^#!.*python3') $(git ls-files "*.py")"
     # W504 and W503 are mutually exclusive (and both disabled by default)
     # explicitly giving '--ignore W504' here is actually more strict than the default
-    # TODO: E402 should be fixed
-    out=$(python3 -m "$PYTHON_STYLE_CHECKER" --max-line-length=415 --ignore E402,W504 $PYFILES) || true
+    out=$(python3 -m "$PYTHON_STYLE_CHECKER" --max-line-length=415 --ignore W504 $PYFILES) || true
     if [ -n "$out" ]; then
         echo "$out" >&2
         echo "not ok 7 $PYTHON_STYLE_CHECKER test"