Don't resume on top of repeated header on top of monolithic overflow.

A repeated table header may have to overlap with monolithic overflow
from the previous page, but actual table content should still resume
*after* the repeated header.

We had code that made sure that we'd resume below monolithic content,
since we temporarily adjust the offset to place the repeated header.
However, if the repeated header is taller than the monolithic overflow,
we're already at the correct offset. Never move the offset back, because
then regular table content might be placed on top of the repeated
header.

Bug: 1458850
Change-Id: Ia01e6ae4ac4498737c67b0ba34b5890b0fc36803
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4793950
Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Commit-Queue: Morten Stenshorne <mstensho@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1185295}