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

This is a reland of 965f2dd775e784aa146f1905cf1013f84a6ab512

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}

Bug: 845472, 908970
Change-Id: Ia84d71d73733d5c326443c3441e3127b700e73ef
Reviewed-on: https://chromium-review.googlesource.com/c/1356718
Commit-Queue: David Jean <djean@chromium.org>
Reviewed-by: Javier Ernesto Flores Robles <javierrobles@chromium.org>
Reviewed-by: Ben Pastene <bpastene@chromium.org>
Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#614677}
6 files changed