[analyzer] Track trivial copy/move constructors and initializer lists in the BugReporter

If an object has a trivial copy/move constructor, it's not inlined
on invocation but a trivial copy is performed instead. This patch
handles trivial copies in the bug reporter by matching the field
regions of the 2 objects involved in the copy/move construction,
and tracking the appropriate region further. This patch also
introduces some support for tracking values in initializer lists.

Differential Revision: https://reviews.llvm.org/D131262