[turbofan] remove one level of indirection in phi inputs

test/unittests/compiler/register-allocator-unittest.cc

Index: test/unittests/compiler/register-allocator-unittest.cc
diff --git a/test/unittests/compiler/register-allocator-unittest.cc b/test/unittests/compiler/register-allocator-unittest.cc
index e198c74ec2d39c32903bf0cdbd0808936c69fc46..c82cc3733ee6b0601fae67c5f901e15c56d73914 100644
--- a/test/unittests/compiler/register-allocator-unittest.cc
+++ b/test/unittests/compiler/register-allocator-unittest.cc
@@ -42,9 +42,9 @@ TEST_F(RegisterAllocatorTest, SimpleLoop) {
     StartLoop(1);
 
     StartBlock();
-    auto phi = Phi(i_reg);
+    auto phi = Phi(i_reg, 2);
     auto ipp = EmitOI(Same(), Reg(phi), Use(DefineConstant()));
-    Extend(phi, ipp);
+    SetInput(phi, 1, ipp);
     EndBlock(Jump(0));
 
     EndLoop();
@@ -206,14 +206,14 @@ TEST_F(RegisterAllocatorTest, RegressionPhisNeedTooManyRegisters) {
     StartBlock();
 
     for (size_t i = 0; i < arraysize(parameters); ++i) {
-      phis[i] = Phi(parameters[i]);
+      phis[i] = Phi(parameters[i], 2);
     }
 
     // Perform some computations.
     // something like phi[i] += const
     for (size_t i = 0; i < arraysize(parameters); ++i) {
       auto result = EmitOI(Same(), Reg(phis[i]), Use(constant));
-      Extend(phis[i], result);
+      SetInput(phis[i], 1, result);
     }
 
     EndBlock(Branch(Reg(DefineConstant()), 1, 2));