IA32 architecture is somewhat special in Dart VM:

• AOT compilation is not supported on IA32.
• Type testing stubs are not supported on IA32.
• Due to a small number of registers, IA32 often has a custom implementation of various stubs or custom code generation patterns which are sufficiently different from other architectures.

Supporting IA32 carries additional burden when adding new features. At the same time, usage of IA32 declines over time.

We should consider if it is still useful to support IA32 architecture in the future versions of Dart, deprecate and eventually drop IA32.

/cc @mit-mit @a-siva @mraleph @mkustermann