Fix warning about dead code when testing on non-wasm32 targets

There are functions that are only used on wasm32 targets, but `cfg`ing them is
more work than just making the modules public, and this is just a testing crate.

crates/typescript-tests/src/lib.rs

@@ -1,5 +1,5 @@
-mod custom_section;
-mod getters_setters;
-mod opt_args_and_ret;
-mod simple_fn;
-mod simple_struct;
+pub mod custom_section;
+pub mod getters_setters;
+pub mod opt_args_and_ret;
+pub mod simple_fn;
+pub mod simple_struct;