[analyzer] If the last store into a region came from a function, step into it.

Previously, if we were tracking stores to a variable 'x', and came across this:

x = foo();

...we would simply emit a note here and stop. Now, we'll step into 'foo' and
continue tracking the returned value from there.

<rdar://problem/12114689>

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@162718 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed