[turbofan] Allow tests to enable/disable instruction scheduling.

test/unittests/compiler/instruction-selector-unittest.cc

Index: test/unittests/compiler/instruction-selector-unittest.cc
diff --git a/test/unittests/compiler/instruction-selector-unittest.cc b/test/unittests/compiler/instruction-selector-unittest.cc
index d2953159fc5adf47763db98bf194f50484e214bf..d0e3bd08e1e3bef3094a05c1800238ad0e4a1514 100644
--- a/test/unittests/compiler/instruction-selector-unittest.cc
+++ b/test/unittests/compiler/instruction-selector-unittest.cc
@@ -41,7 +41,8 @@ InstructionSelectorTest::Stream InstructionSelectorTest::StreamBuilder::Build(
   SourcePositionTable source_position_table(graph());
   InstructionSelector selector(test_->zone(), node_count, &linkage, &sequence,
                                schedule, &source_position_table, nullptr,
-                               source_position_mode, features);
+                               source_position_mode, features,
+                               InstructionSelector::kDisableScheduling);
   selector.SelectInstructions();
   if (FLAG_trace_turbo) {
     OFStream out(stdout);