This is another step towards a kRootRegister on ia32 and removes
kRootRegister from generic interface descriptors.

Drive-by: Better error message for type mismatches in machine graph
verification.
Drive-by: Use PreserveRootIA32 register config for all builtins.

Bug: v8:6666
Change-Id: I920d4d6f3085da9734f6aa3bd3ee020abbc289fc
Reviewed-on: https://chromium-review.googlesource.com/1186330Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55338}