Add Operand->isConsuming() API.

This should be used instead of isLifetimeEnding wherever the code
assumes an owned value is consumed.

isLifetimeEnding should only be used when the code is expected to
handle both owned and guaranteed values.

Author: atrick

include/swift/SIL/SILValue.h

@@ -676,6 +676,11 @@ class OwnershipConstraint {
     return lifetimeConstraint;
   }
 
+  bool isConsuming() const {
+    return ownershipKind == OwnershipKind::Owned
+      && lifetimeConstraint == UseLifetimeConstraint::LifetimeEnding;
+  }
+
   bool satisfiedBy(const Operand *use) const;
 
   bool satisfiesConstraint(ValueOwnershipKind testKind) const {