Revert "Reland "[ios] add credit card test for manual fallback""

This reverts commit 965f2dd775e784aa146f1905cf1013f84a6ab512.

Reason for revert: Still broken, unfortunately: https://crbug.com/909760

Original change's description:
> Reland "[ios] add credit card test for manual fallback"
> 
> This is a reland of 30e1dd180408413c8fce6dbe5b856c048a8ca908
> 
> Adding feature flags to slimnav.
> Revert bug: https://bugs.chromium.org/p/chromium/issues/detail?id=908970
> 
> Original change's description:
> > [ios] add credit card test for manual fallback
> >
> > Also adds AutofillManualFallbackPhaseTwo to test bots.
> >
> > Bug: 845472
> > Change-Id: I6bd05781c09c24c0768e24acfe59efa7ce1da05d
> > Reviewed-on: https://chromium-review.googlesource.com/c/1337347
> > Reviewed-by: Rohit Rao <rohitrao@chromium.org>
> > Reviewed-by: Ben Pastene <bpastene@chromium.org>
> > Reviewed-by: Javier Ernesto Flores Robles <javierrobles@chromium.org>
> > Commit-Queue: David Jean <djean@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#611171}
> 
> TBR=rohitrao@chromium.org
> 
> Bug: 845472,908970
> Change-Id: I2cc0cddf0be8cea447f45f69457afbe19c840f29
> Reviewed-on: https://chromium-review.googlesource.com/c/1352328
> Commit-Queue: Javier Ernesto Flores Robles <javierrobles@chromium.org>
> Reviewed-by: Javier Ernesto Flores Robles <javierrobles@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#611679}

TBR=rohitrao@chromium.org,bpastene@chromium.org,javierrobles@chromium.org,djean@chromium.org

Change-Id: Ie4ab90910a6c9b63c0b15044663c2dab68637ae9
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 845472, 908970
Reviewed-on: https://chromium-review.googlesource.com/c/1352934
Reviewed-by: Ken Rockot <rockot@google.com>
Commit-Queue: Ken Rockot <rockot@google.com>
Cr-Commit-Position: refs/heads/master@{#611741}
6 files changed