LibTest: Handle Crash printing in a private method

Author: https://github.com/mhermier
Commit: c8cabd433a
Pull-request: https://github.com/SerenityOS/serenity/pull/11291

Userland/Libraries/LibTest/CrashTest.h

@@ -30,6 +30,8 @@ public:
     bool run(RunType run_type = RunType::UsingChildProcess);
 
 private:
+    bool do_report(Failure failure);
+
     String m_type;
     Function<Crash::Failure()> m_crash_function;
 };