Merge "Bump default experimental from gnu++2a to gnu++2b." into main am:...

Merge "Bump default experimental from gnu++2a to gnu++2b." into main am: a1d45b8e am: dfb192e8 am: b8b79e70

Original change: https://android-review.googlesource.com/c/platform/build/soong/+/2832038



Change-Id: I75e46f32d402e49bab164f542016dcdb706aec42
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>