[turbofan] Enable concurrent (re)compilation.

src/compiler/ia32/instruction-selector-ia32.cc

Index: src/compiler/ia32/instruction-selector-ia32.cc
diff --git a/src/compiler/ia32/instruction-selector-ia32.cc b/src/compiler/ia32/instruction-selector-ia32.cc
index 8a4899011dcedcd9b7a2e2ab1c244b686442355a..6228670c1b27880a3df6aae065f3d2925ee982e4 100644
--- a/src/compiler/ia32/instruction-selector-ia32.cc
+++ b/src/compiler/ia32/instruction-selector-ia32.cc
@@ -60,11 +60,16 @@ class IA32OperandGenerator final : public OperandGenerator {
       case IrOpcode::kRelocatableInt64Constant:
         return true;
       case IrOpcode::kHeapConstant: {
+// TODO(bmeurer): We must not dereference handles concurrently. If we
+// really have to this here, then we need to find a way to put this
+// information on the HeapConstant node already.
+#if 0
         // Constants in new space cannot be used as immediates in V8 because
         // the GC does not scan code objects when collecting the new generation.
         Handle<HeapObject> value = OpParameter<Handle<HeapObject>>(node);
         Isolate* isolate = value->GetIsolate();
         return !isolate->heap()->InNewSpace(*value);
+#endif
       }
       default:
         return false;