[v16.x-backport] deps: update V8 to 9.4
Backport of https://github.com/nodejs/node/pull/39945 with the addition of two commits to keep ABI, API and ICU 68 compatibility:
- deps: make V8 9.4 abi-compatible with 9.0
- deps: restore minimum ICU version to 68
Diff with
git diff bcb9e9efb4...HEAD -- 'deps/v8/include/cppgc/common.h' 'deps/v8/include/libplatform/libplatform.h' 'deps/v8/include/libplatform/libplatform-export.h' 'deps/v8/include/libplatform/v8-tracing.h' 'deps/v8/include/v8.h' 'deps/v8/include/v8-internal.h' 'deps/v8/include/v8-platform.h' 'deps/v8/include/v8-profiler.h' 'deps/v8/include/v8-version.h' 'deps/v8/include/v8config.h' | gh gist create
https://gist.github.com/targos/76f2dae6cc1ab9c3a52a3502bfb80bec
This is the last V8 version that I'm able to keep compatible with 9.0 with reasonable amount of work. I do not plan to backport V8 9.5 and later to v16.x LTS.
/cc @nodejs/v8-update @addaleax