Reduce import-instr-limit temporarily on amd64

chromeos-chrome fails on amd64 with overflows in R_X86_64_32 relocations.
This can be mitigated by reducing the binary size.
This is just a temporary solution to unblock chrome uprevs on chromeos
until we have a long term solution.
Earlier evaluation of import-instr-limit on chrome showed that reducing
the limit helps to reduce the binary size by a few percent with a very
slight performance loss.

Bug: b/271459198
Change-Id: Id850c27f765da03383c6e9e56ffd12912760b352
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4305496


Reviewed-by: Alan Zhao <ayzhao@google.com>
Commit-Queue: Denis Nikitin <denik@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1112867}