PPC/s390: [builtins] Streamline the construct stubs

Port 366d30c9

Original Commit Message:

    - don't restore the context register after InvokeFunction unless we need
      to for throwing exceptions.
    - manually manage the frame to improve code layout for the fast path

R=verwaest@chromium.org, joransiu@ca.ibm.com, junyan@redhat.com, midawson@redhat.com
BUG=
LOG=N

Change-Id: I2db3ccd8948c21bc7c5be34237f016be305d7e72
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2530873Reviewed-by: Junliang Yan <junyan@redhat.com>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71109}