copy constructors of classes with array members, instead using
ArrayInitLoopExpr to represent the initialization loop.

This exposed a bug in the static analyzer where it was unable to differentiate
between zero-initialized and unknown array values, which has also been fixed
here.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@289618 91177308-0d34-0410-b5e6-96231b3b80d8