By Lucy Papachristou YEREVAN, June 7 (Reuters) - Armenians head to the polls on Sunday in a parliamentary election seen as a test of the government's efforts to forge a peace deal after a crushing military defeat by Azerbaijan three years ago. Polls show Prime Minister Nikol Pashinyan's ruling Civil Contract party leading, backed by up to 32% of voters, with the pro-Russian Strong Armenia party trailing in second place with up to 11%.