[SIL] tuple_addr_constructor reqs lowered addrs.

The instruction exists to express the atomic initialization of a
tuple-typed address in address-lowered mode.  In opaque-values mode,
this is expressed as an assign/store.

Author: nate-chandler

include/swift/SIL/SILBuilder.h

@@ -1672,6 +1672,7 @@ class SILBuilder {
   createTupleAddrConstructor(SILLocation Loc, SILValue DestAddr,
                              ArrayRef<SILValue> Elements,
                              IsInitialization_t IsInitOfDest) {
+    assert(getFunction().getModule().useLoweredAddresses());
     return insert(TupleAddrConstructorInst::create(getSILDebugLocation(Loc),
                                                    DestAddr, Elements,
                                                    IsInitOfDest, getModule()));

lib/SIL/Verifier/SILVerifier.cpp

@@ -3338,6 +3338,8 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
   }
 
   void checkTupleAddrConstructorInst(TupleAddrConstructorInst *taci) {
+    require(F.getModule().useLoweredAddresses(),
+            "tuple_addr_constructor is invalid in opaque values");
     require(taci->getNumElements() > 0,
             "Cannot be applied to tuples that do not contain any real "
             "elements. E.x.: ((), ())");