This CL teaches the respective bytecode handlers and standalone stubs
about BigInts, and collects "kBigInt" feedback for them. However,
Turbofan does not yet care about such feedback, so it is simply converted
to "any" for now (making TF emit stub calls for BigInt operations).

Bug: v8:6791
Change-Id: I6440c108ccd79058d77adc2a6041251db9d5f81d
Reviewed-on: https://chromium-review.googlesource.com/683758Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48173}