[analyzer] Symbolic regions are live if any subregions are live.

RegionStoreManager was only treating a SymbolicRegion's symbel as live
if there was a binding referring to the region itself.

No test case because constraints are currently not being cleaned out
of the constraint manager at all (even if the symbol is legitimately dead).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@163443 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed