Some TLS servers require SNI, but the Golang HTTP client doesn't
include it in the ClientHello when connecting to an IP address. This
change adds a new TLSServerName field to health check definitions to
optionally set it. This fixes#9473.
A golden file makes the expected value easier to work with. This change also
removes a number of shims for enterprise and replaces them with a single one
for the golden filename.
Christopher Broglie