This commit: - Adds test for remotely initiated rekey for IKE and Child SA - Makes IkeTunUtils support building and injecting requests - Adds method to parse hex to long because Long.parseLong cannot handle negative long value Bug: 155821007 Test: atest CtsIkeTestCases Change-Id: I299cf190261ac15397f9ed389adb2c69e94a6507 Merged-In: I299cf190261ac15397f9ed389adb2c69e94a6507 (cherry picked from commit a5bff5a7b46c31dfa4ae692328edfb2b2a6462c8)