Distinguish different kinds of l-value reads in SILGen.

This is NFC for now, but I plan to build on this to (1) immediately
remove some unnecessary materialization and loads of the base value
and (2) to allow clients to load a borrowed value.

lib/SILGen/SILGenForeignError.cpp

@@ -100,7 +100,7 @@ static void emitStoreToForeignErrorSlot(SILGenFunction &SGF,
     SGF.emitPropertyLValue(loc, ManagedValue::forUnmanaged(foreignErrorSlot),
                            bridgedErrorPtrType, pointeeProperty,
                            LValueOptions(),
-                           AccessKind::Write,
+                           SGFAccessKind::Write,
                            AccessSemantics::Ordinary);
   RValue rvalue(SGF, loc, bridgedErrorProto,
                 SGF.emitManagedRValueWithCleanup(bridgedError));