Move CreditCard function to util (/autofill)

When buidling using jumbo, files gets merged and functions
with the same name may end up in the same namespace and
conflict. This happens for the function IsCreditCardExporationType
in:
components/autofill/core/browser/form_structure.cc
components/autofill/core/browser/autofill_manager.cc

Since the functions are identical they are moved to a shared
util file. Since the function needs
components/autofill/core/browser/field_types.h it cannot be
moved to components/autofill/core/common.

Bug: 869381
Change-Id: I69492fbc8af0ed9289504cb6aba3e745acb17b24
Reviewed-on: https://chromium-review.googlesource.com/1158364
Commit-Queue: Oscar Johansson <oscarj@opera.com>
Reviewed-by: Vadym Doroshenko <dvadym@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579778}
4 files changed