[compiler] Remove support for concurrent OSR.

src/full-codegen/x64/full-codegen-x64.cc

Index: src/full-codegen/x64/full-codegen-x64.cc
diff --git a/src/full-codegen/x64/full-codegen-x64.cc b/src/full-codegen/x64/full-codegen-x64.cc
index 2ae38dd776384c4ac372b78c038e9d72ddf76428..ed34160762bee6f36660c002e869cff47095d5e5 100644
--- a/src/full-codegen/x64/full-codegen-x64.cc
+++ b/src/full-codegen/x64/full-codegen-x64.cc
@@ -3996,7 +3996,6 @@ void BackEdgeTable::PatchAt(Code* unoptimized_code,
       *jns_offset_address = kJnsOffset;
       break;
     case ON_STACK_REPLACEMENT:
-    case OSR_AFTER_STACK_CHECK:
       //     sub <profiling_counter>, <delta>  ;; Not changed
       //     nop
       //     nop
@@ -4034,16 +4033,10 @@ BackEdgeTable::BackEdgeState BackEdgeTable::GetBackEdgeState(
   DCHECK_EQ(kNopByteOne, *jns_instr_address);
   DCHECK_EQ(kNopByteTwo, *(call_target_address - 2));
 
-  if (Assembler::target_address_at(call_target_address,
-                                   unoptimized_code) ==
-      isolate->builtins()->OnStackReplacement()->entry()) {
-    return ON_STACK_REPLACEMENT;
-  }
-
-  DCHECK_EQ(isolate->builtins()->OsrAfterStackCheck()->entry(),
-            Assembler::target_address_at(call_target_address,
-                                         unoptimized_code));
-  return OSR_AFTER_STACK_CHECK;
+  DCHECK_EQ(
+      isolate->builtins()->OnStackReplacement()->entry(),
+      Assembler::target_address_at(call_target_address, unoptimized_code));
+  return ON_STACK_REPLACEMENT;
 }
 
 }  // namespace internal