[inspector] deoptimize function in Debug::PrepareStepIn

test/inspector/inspector.status

 # Copyright 2016 the V8 project authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 [
 ['mode == debug', {
   # Issue 6168. Crash.
   'runtime/await-promise': [SKIP],
 }],
 
 ##############################################################################
 ['variant != default', {
   # Issue 6165.
   'cpu-profiler/coverage': [PASS, FAIL],
   # Issue 6166.
   'debugger/asm-js-breakpoint-during-exec': [PASS, FAIL],
   'debugger/asm-js-stack': [PASS, FAIL],
   # Issue 6167.
   'debugger/eval-scopes': [PASS, FAIL],
   'debugger/scope-skip-variables-with-empty-name': [PASS, FAIL],
   'debugger/update-call-frame-scopes': [PASS, FAIL],
   'debugger/side-effect-free-debug-evaluate': [PASS, FAIL],
   # Issue 6170. Crash.
   'cpu-profiler/console-profile': [SKIP],
   'cpu-profiler/console-profile-end-parameterless-crash': [SKIP],
-  # Issue 6171. Timeout.
-  'debugger/set-blackbox-patterns': [SKIP],
 }],  # variant != default
 
 ##############################################################################
 ['variant == wasm_traps', {
   '*': [SKIP],
 }],  # variant == wasm_traps
 
 ]