Avoid accessing Isolate in source position logging.

src/crankshaft/x87/lithium-codegen-x87.cc

Index: src/crankshaft/x87/lithium-codegen-x87.cc
diff --git a/src/crankshaft/x87/lithium-codegen-x87.cc b/src/crankshaft/x87/lithium-codegen-x87.cc
index a754856587990d7269000b37fa0ec236b91c0db9..f6aa9639b3dd9640271389068c311b0c618538a4 100644
--- a/src/crankshaft/x87/lithium-codegen-x87.cc
+++ b/src/crankshaft/x87/lithium-codegen-x87.cc
@@ -68,9 +68,6 @@ void LCodeGen::FinishCode(Handle<Code> code) {
   DCHECK(is_done());
   code->set_stack_slots(GetTotalFrameSlotCount());
   code->set_safepoint_table_offset(safepoints_.GetCodeOffset());
-  Handle<ByteArray> source_positions =
-      source_position_table_builder_.ToSourcePositionTable();
-  code->set_source_position_table(*source_positions);
   PopulateDeoptimizationData(code);
   if (info()->ShouldEnsureSpaceForLazyDeopt()) {
     Deoptimizer::EnsureRelocSpaceForLazyDeoptimization(code);