wasm: log stack traces for exceptions

This is very useful for debugging.

Change-Id: I4861afb9bd2b4e757a962d81583a8b12958f9f1c
Reviewed-by: Mikołaj Boc <Mikolaj.Boc@qt.io>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
(cherry picked from commit 9e0cb768cd3098e6de253913621887351f719d72)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/plugins/platforms/wasm/wasm_shell.html

@@ -63,6 +63,7 @@
                 });
             } catch (e) {
                 console.error(e);
+                console.error(e.stack);
                 status.innerHTML = e.message;
                 showUi(spinner);
             }