AesGcm, AesCcm (dotnet/corefx#31389)

AesGcm, AesCcm (dotnet/corefx#31389)

* AesGcm, AesCcm

* add osx stubs

* disable tests on osx and desktop (APIs not there/not supported)

* TagByteSizes on OSX

* fix TagByteSizes compilation error

* apply review feedback

* fix typo when setting tag/nonce length in ccm

* add missing SetCcmTagLength

* attempt to detect if ccm is available on Ubuntu 14.04

* disable tests on ubuntu 14.04, attempt for osx support

* attempt to fix osx

* fix osx

* review feedback

* disable new ccm testcases on ubuntu 14.04

* attempt to make Ubuntu 14.04 work

* add Interop.Initialization to OSX

* fix KeySizeHelpers after merge conflict

Signed-off-by: dotnet-bot <dotnet-bot@microsoft.com>