Compute the def-use list on-demand by walking the dominator tree.

runtime/vm/intermediate_language_test.cc

Index: runtime/vm/intermediate_language_test.cc
diff --git a/runtime/vm/intermediate_language_test.cc b/runtime/vm/intermediate_language_test.cc
index bea3873a395831aa1d61702872690826d9269387..13eb7f4cd1077ba2f2a2215191dd8624ac60e5aa 100644
--- a/runtime/vm/intermediate_language_test.cc
+++ b/runtime/vm/intermediate_language_test.cc
@@ -17,36 +17,6 @@ TEST_CASE(InstructionTests) {
   EXPECT(!bind_instr->IsBlockEntry());
 }
 
-TEST_CASE(DefUseTests) {
-  Definition* def1 = new PhiInstr(0);
-  Definition* def2 = new PhiInstr(0);
-  EXPECT(def1->use_list() == NULL);
-  EXPECT(def2->use_list() == NULL);
-  UseVal* use1 = new UseVal(def1);
-  EXPECT(def1->use_list() == use1);
-  EXPECT(def1->use_list()->next_use() == NULL);
-  UseVal* use2 = new UseVal(def1);
-  EXPECT(def1->use_list()->next_use()->next_use() == NULL);
-  UseVal* use3 = new UseVal(def1);
-  EXPECT(def1->use_list()->next_use()->next_use()->next_use() == NULL);
-  use1->RemoveFromUseList();
-  EXPECT(def1->use_list()->next_use()->next_use() == NULL);
-  use3->SetDefinition(def2);
-  EXPECT(def1->use_list() == use2);
-  EXPECT(def1->use_list()->next_use() == NULL);
-  EXPECT(def2->use_list() == use3);
-  EXPECT(def2->use_list()->next_use() == NULL);
-  BindInstr* bind =
-      new BindInstr(BindInstr::kUsed, new BooleanNegateComp(use2));
-  bind->RemoveInputUses();
-  EXPECT(def1->use_list() == NULL);
-  // Test replacing with a definition without uses.
-  UseVal* use4 = new UseVal(def2);
-  def2->ReplaceUsesWith(def1);
-  EXPECT(def1->use_list() == use4);
-  EXPECT(def2->use_list() == NULL);
-  EXPECT(use4->definition() == def1);
-}
 
 TEST_CASE(OptimizationTests) {
   Definition* def1 = new PhiInstr(0);