Avoid accessing Isolate in source position logging.

src/crankshaft/ia32/lithium-codegen-ia32.cc

Index: src/crankshaft/ia32/lithium-codegen-ia32.cc
diff --git a/src/crankshaft/ia32/lithium-codegen-ia32.cc b/src/crankshaft/ia32/lithium-codegen-ia32.cc
index f93fea42d92d9af823fa4e317d83e37976d69072..8233659ddbe22c8c4f603d6d6b80fe232e3cbb73 100644
--- a/src/crankshaft/ia32/lithium-codegen-ia32.cc
+++ b/src/crankshaft/ia32/lithium-codegen-ia32.cc
@@ -69,9 +69,6 @@ void LCodeGen::FinishCode(Handle<Code> code) {
   code->set_stack_slots(GetTotalFrameSlotCount());
   code->set_safepoint_table_offset(safepoints_.GetCodeOffset());
   PopulateDeoptimizationData(code);
-  Handle<ByteArray> source_positions =
-      source_position_table_builder_.ToSourcePositionTable();
-  code->set_source_position_table(*source_positions);
   if (info()->ShouldEnsureSpaceForLazyDeopt()) {
     Deoptimizer::EnsureRelocSpaceForLazyDeoptimization(code);
   }