Tests should check if the provider used the key passed to fi_mr_reg

[arun ilango]

unit/mr_test and other tests that call fi_mr_reg should check if the provider used the key passed to fi_mr_reg (app_key == fi_mr_key(mr)).

This applies for providers that support FI_MR_SCALABLE ( version < 1.5) or doesn't require the mode bit FI_MR_PROV_KEY (version >= 1.5)