[analyzer] Make sure a materialized temporary matches its bindings.

This is a follow-up to r175830, which made sure a temporary object region
created for, say, a struct rvalue matched up with the initial bindings
being stored into it. This does the same for the case in which the AST
actually tells us that we need to create a temporary via a
MaterializeObjectExpr. I've unified the two code paths and moved a static
helper function onto ExprEngine.

This also caused a bit of test churn, causing us to go back to describing
temporary regions without a 'const' qualifier. This seems acceptable; it's
our behavior from a few months ago.

<rdar://problem/13265460> (part 2)

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@175854 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Analysis/stack-addr-ps.cpp b/test/Analysis/stack-addr-ps.cpp
index 9dd63f8..7aefea5 100644
--- a/test/Analysis/stack-addr-ps.cpp
+++ b/test/Analysis/stack-addr-ps.cpp
@@ -22,17 +22,17 @@
 
 int get_value();
 
-const int &get_reference1() { return get_value(); } // expected-warning{{Address of stack memory associated with temporary object of type 'const int' returned}} expected-warning {{returning reference to local temporary}}
+const int &get_reference1() { return get_value(); } // expected-warning{{Address of stack memory associated with temporary object of type 'int' returned}} expected-warning {{returning reference to local temporary}}
 
 const int &get_reference2() {
   const int &x = get_value(); // expected-note {{binding reference variable 'x' here}}
-  return x; // expected-warning{{Address of stack memory associated with temporary object of type 'const int' returned}} expected-warning {{returning reference to local temporary}}
+  return x; // expected-warning{{Address of stack memory associated with temporary object of type 'int' returned}} expected-warning {{returning reference to local temporary}}
 }
 
 const int &get_reference3() {
   const int &x1 = get_value(); // expected-note {{binding reference variable 'x1' here}}
   const int &x2 = x1; // expected-note {{binding reference variable 'x2' here}}
-  return x2; // expected-warning{{Address of stack memory associated with temporary object of type 'const int' returned}} expected-warning {{returning reference to local temporary}}
+  return x2; // expected-warning{{Address of stack memory associated with temporary object of type 'int' returned}} expected-warning {{returning reference to local temporary}}
 }
 
 int global_var;
@@ -56,7 +56,7 @@
 const int *f4() {
   const int &x1 = get_value(); // expected-note {{binding reference variable 'x1' here}}
   const int &x2 = x1; // expected-note {{binding reference variable 'x2' here}}
-  return &x2; // expected-warning{{Address of stack memory associated with temporary object of type 'const int' returned}} expected-warning {{returning address of local temporary}}
+  return &x2; // expected-warning{{Address of stack memory associated with temporary object of type 'int' returned}} expected-warning {{returning address of local temporary}}
 }
 
 struct S {