[JENKINS-3265] [JENKINS-17341] Even if older plugins throw an NPE during reload, continue loading job.

removed the noAnime() conversions, so we can rely on the compiler to warn us, if we forget a case here

Add convenience method for checking if object is MatrixProject

[FIXED JENKINS-18671] Clock Difference broken on Manage Nodes page

against incorrect values if times are ever compared between different JVM nodes

System.nanos() returns a monotonically increasing value that is not related
to wallclock time. Use System.currentTimeMillis() instead.

Unlike the bug I originally reproduced, in which the parent had some builds
but the context in which the new build was scheduled omits a parent,
this seems to be due to a case in which there is no build record at all for the parent.
No idea how that could happen (getLastBuild should return even a running, failed, or aborted build),
but @treydock reports a stack trace in 1.509.2 which implies this.
So fixing null safety; will not prevent an exception but will report it more gracefully.