[turbofan] Add and use bytecode loop assigment analysis

src/interpreter/bytecode-array-accessor.cc

Index: src/interpreter/bytecode-array-accessor.cc
diff --git a/src/interpreter/bytecode-array-accessor.cc b/src/interpreter/bytecode-array-accessor.cc
index 1d19f7d4b0ccc6cf853a886d67759bdc26d1b7a0..8e6a7328614131ed1677d01e6f32b5f0b82e278f 100644
--- a/src/interpreter/bytecode-array-accessor.cc
+++ b/src/interpreter/bytecode-array-accessor.cc
@@ -189,6 +189,11 @@ int BytecodeArrayAccessor::GetJumpTargetOffset() const {
   }
 }
 
+bool BytecodeArrayAccessor::OffsetWithinBytecode(int offset) const {
+  return current_offset() <= offset &&
+         offset < current_offset() + current_bytecode_size();
+}
+
 std::ostream& BytecodeArrayAccessor::PrintTo(std::ostream& os) const {
   return BytecodeDecoder::Decode(
       os, bytecode_array()->GetFirstBytecodeAddress() + bytecode_offset_,