Change excepted result on R for testVoiceMailNumber

If phone type is not gsm, getVoiceMailAlphaTag() will always
return the string of R.string.defaultVoiceMailAlphaTag. So it
does not read it from SIMrecords, it get default value “Voicemail”.

Bug: 160386097
Change-Id: I5a2e7ccb2e5652db06274d7eb1874bc72508538b