Rather than having periodic constant pool checks that almost always fail
(because the constant pool deadline isn't close enough, or even because
there's no constant pool to emit at all), set a single deadline on the
first constant pool insertion which expires just before the maximum
distance to the constant pool. Constant pool checks around unconditional
jumps happen irrespective of this deadline.

In particular, this is made possible by fixing the incorrect assumption
that the constant pool can be emitted out of order. The new assumption
(that the emission is in-order) is validated with a CHECK.

Bug: v8:11420
Change-Id: I061dd0b8c3476ba95ee1acfb3b485d8ba2adda91
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2844665
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74141}