Set instantiationPoint for tuple TypeSymbols

See e.g. test/library/standard/Map/testIterators.chpl which
failed before this change, because the '=' resolved in the array
initializer was not getting the correct instantiation point for the type.

compiler/resolution/tuples.cpp

@@ -373,6 +373,7 @@ TupleInfo getTupleInfo(std::vector<TypeSymbol*>& args,
     // Create the TypeSymbol
     TypeSymbol* newTypeSymbol = new TypeSymbol(name.c_str(), newType);
     newTypeSymbol->cname = astr(cname.c_str());
+    newTypeSymbol->instantiationPoint = instantiationPoint;
 
     // Set appropriate flags on the new TypeSymbol
     newTypeSymbol->addFlag(FLAG_ALLOW_REF);