Remove trap registration from wasmtime crate (#903)

Our trampoline shims no longer have traps baked into them so this is
largely all dead code now at this point.

crates/api/src/trampoline/mod.rs

@@ -5,7 +5,6 @@ mod func;
 mod global;
 mod memory;
 mod table;
-mod trap;
 
 use self::func::create_handle_with_function;
 use self::global::create_global;