Make tests with std::move only run with C++11.

The corresponding source files all use std::move.

diff --git a/tests/base/index_set_24.output b/tests/base/index_set_24.with_cxx11=true.output
similarity index 100%
rename from tests/base/index_set_24.output
rename to tests/base/index_set_24.with_cxx11=true.output

diff --git a/tests/lac/block_indices.output b/tests/lac/block_indices.with_cxx11=true.output
similarity index 100%
rename from tests/lac/block_indices.output
rename to tests/lac/block_indices.with_cxx11=true.output