Separate root domain and rfactor domain in TransformPrinter (#1716)

I feel that this could be helpful for debugging. Using the example that breaks our system in csarofeen#1692

Before
```
TransformPrinter : 
T0_g[ iS0{i1}, iS1{i2} ]
 root domain : (iS0{i1},iS1{i2})
T2_l[ iS11{( ceilDiv(i1, 3) )}, iS15{( 3 * ( ceilDiv(i2, 4) ) )}rf, rS14{4}rf ]
 root domain : (iS9{i1},iS15{( 3 * ( ceilDiv(i2, 4) ) )}rf,rS14{4}rf)
  Split: iS9{i1} by factor 3 -> iS11{( ceilDiv(i1, 3) )}, iS12{3}, start offset: 0, stop offset: 0
T1_g[ rS17{( ceilDiv(i1, 3) )}, rS19{( 3 * ( ceilDiv(i2, 4) ) )} ]
 root domain : (rS16{i1},rS19{( 3 * ( ceilDiv(i2, 4) ) )})
  Split: rS16{i1} by factor 3 -> rS17{( ceilDiv(i1, 3) )}, rS18{3}, start offset: 0, stop offset: 0
}
```

After:
```
TransformPrinter : 
T0_g[ iS0{i1}, iS1{i2} ]
 root domain : (iS0{i1},iS1{i2})
T2_l[ iS11{( ceilDiv(i1, 3) )}, iS15{( 3 * ( ceilDiv(i2, 4) ) )}rf, rS14{4}rf ]
 root domain : (iS9{i1},rS10{i2}rf)
  Split: iS9{i1} by factor 3 -> iS11{( ceilDiv(i1, 3) )}, iS12{3}, start offset: 0, stop offset: 0
  Split: rS10{i2}rf by factor 4 -> iS13{( ceilDiv(i2, 4) )}rf, rS14{4}rf, start offset: 0, stop offset: 0
  Merge: iS12{3} and iS13{( ceilDiv(i2, 4) )}rf -> iS15{( 3 * ( ceilDiv(i2, 4) ) )}rf
 rfactor domain : (iS9{i1},iS15{( 3 * ( ceilDiv(i2, 4) ) )}rf,rS14{4}rf)
  Split: iS9{i1} by factor 3 -> iS11{( ceilDiv(i1, 3) )}, iS12{3}, start offset: 0, stop offset: 0
T1_g[ rS17{( ceilDiv(i1, 3) )}, rS19{( 3 * ( ceilDiv(i2, 4) ) )} ]
 root domain : (rS16{i1},rS19{( 3 * ( ceilDiv(i2, 4) ) )})
  Split: rS16{i1} by factor 3 -> rS17{( ceilDiv(i1, 3) )}, rS18{3}, start offset: 0, stop offset: 0
}
```

torch/csrc/jit/codegen/cuda/ir_iostream.cpp

@@ -767,11 +767,7 @@ void IrTransformPrinter::handle(Fusion* f) {
 }
 
 void IrTransformPrinter::printTransforms(TensorView* tv) {
-  auto root_domain = tv->getMaybeRFactorDomain();
-  auto all_exp = DependencyCheck::getAllExprsBetween(
-      {root_domain.begin(), root_domain.end()},
-      {tv->domain()->domain().begin(), tv->domain()->domain().end()});
-
+  auto root_domain = tv->domain()->getRootDomain();
   os() << " root domain : (";
   for (const auto root_idx : c10::irange(root_domain.size())) {
     IrPrinter::handle(root_domain[root_idx]);
@@ -781,6 +777,33 @@ void IrTransformPrinter::printTransforms(TensorView* tv) {
   }
   os() << ")\n";
 
+  if (tv->hasRFactor()) {
+    auto rfactor_domain = tv->domain()->getRFactorDomain();
+
+    auto all_exp = DependencyCheck::getAllExprsBetween(
+        {root_domain.begin(), root_domain.end()},
+        {rfactor_domain.begin(), rfactor_domain.end()});
+
+    for (auto exp : all_exp) {
+      os() << "  ";
+      IrPrinter::handle(exp);
+    }
+
+    os() << " rfactor domain : (";
+    for (const auto root_idx : c10::irange(rfactor_domain.size())) {
+      IrPrinter::handle(rfactor_domain[root_idx]);
+      if (root_idx + 1 < rfactor_domain.size()) {
+        os() << ",";
+      }
+    }
+    os() << ")\n";
+  }
+
+  auto from = tv->getMaybeRFactorDomain();
+  auto all_exp = DependencyCheck::getAllExprsBetween(
+      {from.begin(), from.end()},
+      {tv->domain()->domain().begin(), tv->domain()->domain().end()});
+
   for (auto exp : all_exp) {
     os() << "  ";
     IrPrinter::handle(exp);