tools/ci: Test math constants with MICROPY_OBJ_REPR_D.

tools/ci.sh

@@ -467,7 +467,7 @@ function ci_unix_coverage_32bit_run_native_mpy_tests {
 
 function ci_unix_nanbox_build {
     # Use Python 2 to check that it can run the build scripts
-    ci_unix_build_helper PYTHON=python2 VARIANT=nanbox
+    ci_unix_build_helper PYTHON=python2 VARIANT=nanbox CFLAGS_EXTRA="-DMICROPY_PY_MATH_CONSTANTS=1"
     ci_unix_build_ffi_lib_helper gcc -m32
 }