Stop sending non-UTF-8 prefixes in func tests
Stop sending non-UTF-8 prefixes in func tests

Previously, we'd (with high likelihood) cut it off midway through
a codepoint.

Change-Id: Iba4cce213dce204d7d1b53a937bfbe537276f0f3

tipabu/swift,tipabu/swift,swiftstack/swift,openstack/swift,openstack/swift,openstack/swift,swiftstack/swift,tipabu/swift,swiftstack/swift,tipabu/swift,openstack/swift