Adds additional sanitization for Zygote command arguments.

Previously we were only insuring that the arguments provided to the
Zygote didn't contain any newlines.  This adds additional checks for
carriage returns and standalone integer arguments to protect against
malicious argument and packet injection respectively.

Bug: 130164289
Test: m & flash & boot & check logs
Change-Id: I4055c50d52db0047c02c11096710fd07b429660c