Add test for math module registration

Added a new test `test_math_module_registration` in `stdlib/tests/stdlib_tests.rs`
to verify that `register_math` correctly populates the `std.math` module with all expected functions and properties.

Co-authored-by: Tcode-Motion <188012755+Tcode-Motion@users.noreply.github.com>

Author: google-labs-jules[bot]