`CodeStubAssembler::ToInteger_Inline` performs a `TaggedIsSmi` check,
and calls `ToInteger` with the appropriate truncation mode if the
input is not a Smi.

When we already know we’re dealing with something that’s not a Smi,
this check is redundant, and we can use
`CallBuiltin(Builtins::kToInteger*)` directly.

Bug: v8:7310
Change-Id: If538e39bcb738014bd03f10edd0051dac72b7ea3
Reviewed-on: https://chromium-review.googlesource.com/934901
Commit-Queue: Mathias Bynens <mathias@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51535}