Revert of [turbofan] Run everything after representation selection concurrently.

src/compiler/instruction.cc

Index: src/compiler/instruction.cc
diff --git a/src/compiler/instruction.cc b/src/compiler/instruction.cc
index 818d9cc98f19c3b97ee46053711e858fd041f963..994ade6a3f7e90879e4192fe9f8859d4012e994d 100644
--- a/src/compiler/instruction.cc
+++ b/src/compiler/instruction.cc
@@ -513,16 +513,6 @@
 }
 #endif
 
-Handle<HeapObject> Constant::ToHeapObject() const {
-  DCHECK_EQ(kHeapObject, type());
-  Handle<HeapObject> value(
-      bit_cast<HeapObject**>(static_cast<intptr_t>(value_)));
-  if (value->IsConsString()) {
-    value = String::Flatten(Handle<String>::cast(value), TENURED);
-  }
-  return value;
-}
-
 std::ostream& operator<<(std::ostream& os, const Constant& constant) {
   switch (constant.type()) {
     case Constant::kInt32: