test(api): rename assertRequestParam to assertInvalidRequestParam
test(api): rename assertRequestParam to assertInvalidRequestParam

Closes #280

moander/fxa-oauth-server,moander/fxa-oauth-server,rishibaldawa/fxa-oauth-server,mozilla/fxa-auth-server,mozilla/fxa-auth-server,chilts/fxa-oauth-server,mozilla/fxa-auth-server,rishibaldawa/fxa-oauth-server,chilts/fxa-oauth-server,mozilla/fxa-auth-server