Let go_binary's executable bit depend on `linkmode` (#3143) If a go_binary's `linkmode` is neither `normal` nor `pie`, the resulting file can't be executed. In this case, `executable` should be set to `False` on the go_binary rule so that Bazel doesn't create a runfiles tree for the targets and does not include e.g. a resulting static library in the runfiles of dependants.