Fix dotnet/coreclr#4496 (dotnet/coreclr#4503)

Fix dotnet/coreclr#4496 (dotnet/coreclr#4503)

* Fix dotnet/coreclr#4496

This commit revises legecy codegen to inserts a bkpt instruction if the current BB
and next BB is not in the same exception handling region.

This code is backported from ARM64 codegen.

* Update ControlPcIsUnwound in UnwindManagedExceptionPassX

* Enable only for ARM32

Enable the patch only for ARM32 in order to fix build break in other
architecture.

Commit migrated from https://github.com/dotnet/coreclr/commit/0a889368329270f766686f45f69a47082d18e252