Revert of [turbofan] Splinter into one range.

test/unittests/compiler/live-range-unittest.cc

Index: test/unittests/compiler/live-range-unittest.cc
diff --git a/test/unittests/compiler/live-range-unittest.cc b/test/unittests/compiler/live-range-unittest.cc
index e802aedff19d8cd088dda11df92aa847e2b1c8bc..886a8121c7c4e0f36f0da1989c07654fb1784272 100644
--- a/test/unittests/compiler/live-range-unittest.cc
+++ b/test/unittests/compiler/live-range-unittest.cc
@@ -32,14 +32,11 @@
 
   TopLevelLiveRange* Splinter(TopLevelLiveRange* top, int start, int end,
                               int new_id = 0) {
-    if (top->splinter() == nullptr) {
-      TopLevelLiveRange* ret =
-          new (zone()) TopLevelLiveRange(new_id, MachineType::kRepTagged);
-      top->SetSplinter(ret);
-    }
+    TopLevelLiveRange* ret =
+        new (zone()) TopLevelLiveRange(new_id, MachineType::kRepTagged);
     top->Splinter(LifetimePosition::FromInt(start),
-                  LifetimePosition::FromInt(end), zone());
-    return top->splinter();
+                  LifetimePosition::FromInt(end), ret, zone());
+    return ret;
   }
 
   // Ranges first and second match structurally.
@@ -380,25 +377,6 @@
 }
 
 
-TEST_F(LiveRangeUnitTest, SplinterMergeMultipleTimes) {
-  TopLevelLiveRange* range =
-      TestRangeBuilder(zone()).Add(0, 3).Add(5, 10).Add(12, 16).Build();
-  Splinter(range, 4, 6);
-  Splinter(range, 8, 14);
-  TopLevelLiveRange* splinter = range->splinter();
-  EXPECT_EQ(nullptr, range->next());
-  EXPECT_EQ(nullptr, splinter->next());
-  EXPECT_EQ(range, splinter->splintered_from());
-
-  TopLevelLiveRange* expected_source =
-      TestRangeBuilder(zone()).Add(0, 3).Add(6, 8).Add(14, 16).Build();
-  TopLevelLiveRange* expected_splinter =
-      TestRangeBuilder(zone()).Add(5, 6).Add(8, 10).Add(12, 14).Build();
-  EXPECT_TRUE(RangesMatch(expected_source, range));
-  EXPECT_TRUE(RangesMatch(expected_splinter, splinter));
-}
-
-
 TEST_F(LiveRangeUnitTest, MergeMultipleIntervalsRight) {
   TopLevelLiveRange* original =
       TestRangeBuilder(zone()).Add(0, 3).Add(5, 8).Build();
@@ -438,9 +416,8 @@
 
   TopLevelLiveRange* splinter =
       new (zone()) TopLevelLiveRange(101, MachineType::kRepTagged);
-  vreg->SetSplinter(splinter);
   vreg->Splinter(LifetimePosition::FromInt(4), LifetimePosition::FromInt(12),
-                 zone());
+                 splinter, zone());
 
   EXPECT_EQ(101, splinter->vreg());
   EXPECT_EQ(1, splinter->relative_id());