Fix using reactors with both surface and gas phase chemistry with YAML input

[speth]

Changes proposed in this pull request

• Remove check that gas phase is the first phase in a reactor surface InterfaceKinetics object
• Change a regression test to exercise the case where this condition is not met

The functions for creating InterfaceKinetics objects from YAML input files results in having the surface (reacting) phase as the first phase, in contrast to the functions for creating these objects from CTI/XML files, which put the surface last. This led to a few errors as identified by @ischoegl, which were fixed by @bryanwweber in #905.

However, there was actually a check in Reactor::initialize that was meant to make sure that the InterfaceKinetics object was ordered such that the gas phase came first, as would occur with CTI input files. It just turns out that the examples which were exercising this only include reactors where there are no gas phase reactions, and this check was erroneously not running in that case. But thanks to #905, we can remove it now. I noticed this problem while trying to run the Matlab surfreactor.m example.

Checklist

• There is a clear use-case for this code change
• The commit message has a short title & references relevant issues
• Build passes (scons build & scons test) and unit tests address code coverage
• The pull request is ready for review