Closure compiler build error for Web platform in current dev branch

[akien-mga]

Godot version

4.2.beta1 (b137180), didn't test newer but I expect still reproducible

System information

Fedora 36, Emscripten 3.1.18

Issue description

When building the web editor for 4.2-beta1 on the official buildsystem with Emscripten 3.1.18, I ran into this issue with use_closure_compiler=yes (which we use by default for the editor on official builds).

[Time elapsed: 00:13:56.562]
building:ERROR: Closure compiler run failed:

building:ERROR: /tmp/emscripten_temp_ganlltx7/godot.web.editor.wasm32.js.pgrow.js:7828:24: ERROR - [JSC_LANGUAGE_FEATURE] This language feature is only supported for ECMASCRIPT_2020 mode or better: bigint.
  7828|     HEAP64[b + 2 * i] = 1n;
                                ^

/tmp/emscripten_temp_ganlltx7/godot.web.editor.wasm32.js.pgrow.js:7831:24: ERROR - [JSC_LANGUAGE_FEATURE] This language feature is only supported for ECMASCRIPT_2020 mode or better: bigint.
  7831|     HEAP64[b + 2 * i] = 0n;
                                ^

2 error(s), 0 warning(s)

em++: error: closure compiler failed (rc: 2): /root/emsdk/node/14.18.2_64bit/bin/node --max_old_space_size=8192 /root/emsdk/upstream/emscripten/node_modules/.bin/google-closure-compiler --compilation_level ADVANCED_OPTIMIZATIONS --language_in ECMASCRIPT_2020 --language_out NO_TRANSPILE --emit_use_strict=false --externs /root/emsdk/upstream/emscripten/src/closure-externs/closure-externs.js --language_in ECMASCRIPT6 --externs /root/godot0/modules/webxr/native/webxr.externs.js --externs /root/godot0/platform/web/js/libs/library_godot_webgl2.externs.js --js /tmp/emscripten_temp_ganlltx7/godot.web.editor.wasm32.js.pgrow.js --js_output_file tmp4t1u5yfz.cc.js --formatting PRETTY_PRINT
scons: *** [bin/godot.web.editor.wasm32.js] Error 1

This must have been introduced between 4.2-dev6 and 4.2-beta1. I haven't tested latest master but I expect it may still be reproducible.

Steps to reproduce

• Setup Emscripten 3.1.18, or possibly other versions might have the same issue
• scons target=editor use_closure_compiler=yes production=yes

Minimal reproduction project

n/a