Handle memory errors occurring in wasm scanners

* In WASM, use a custom, simple malloc implementation that lets us
  expicitly reset the heap with a new start location.
* When a WASM call traps or errors, propagate that as a parse failure.
* Reset the WASM heap after every parse.

Co-authored-by: Conrad <conrad@zed.dev>

cli/src/wasm.rs

@@ -62,6 +62,7 @@ pub fn compile_language_to_wasm(
         "__cxa_atexit",
         "abort",
         "emscripten_notify_memory_growth",
+        "tree_sitter_debug_message",
         "proc_exit",
     ];