[interpreter] Add explicit OSR polling bytecode.

src/interpreter/interpreter-assembler.h

Index: src/interpreter/interpreter-assembler.h
diff --git a/src/interpreter/interpreter-assembler.h b/src/interpreter/interpreter-assembler.h
index 679fb5eac287bde7e50e1bd7cd3f99cd557d8578..110c80b6777ae9b34bec06eb2076cbb9c28f567c 100644
--- a/src/interpreter/interpreter-assembler.h
+++ b/src/interpreter/interpreter-assembler.h
@@ -146,6 +146,9 @@ class InterpreterAssembler : public CodeStubAssembler {
   // Updates the profiler interrupt budget for a return.
   void UpdateInterruptBudgetOnReturn();
 
+  // Returns the OSR nesting level from the bytecode header.
+  compiler::Node* LoadOSRNestingLevel();
+
   // Dispatch to the bytecode.
   compiler::Node* Dispatch();