Libraries: Use default constructors/destructors in LibCoredump

https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#cother-other-default-operation-rules

"The compiler is more likely to get the default semantics right and
you cannot implement these functions better than the compiler."

Userland/Libraries/LibCoredump/Backtrace.cpp

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2020, Linus Groh <linusg@serenityos.org>
+ * Copyright (c) 2022, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -91,10 +92,6 @@ Backtrace::Backtrace(const Reader& coredump, const ELF::Core::ThreadInfo& thread
     }
 }
 
-Backtrace::~Backtrace()
-{
-}
-
 void Backtrace::add_entry(const Reader& coredump, FlatPtr ip)
 {
     auto ip_region = coredump.region_containing(ip);

Userland/Libraries/LibCoredump/Backtrace.h

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2020, Linus Groh <linusg@serenityos.org>
+ * Copyright (c) 2022, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -38,7 +39,7 @@ public:
     };
 
     Backtrace(const Reader&, const ELF::Core::ThreadInfo&, Function<void(size_t, size_t)> on_progress = {});
-    ~Backtrace();
+    ~Backtrace() = default;
 
     ELF::Core::ThreadInfo const& thread_info() const { return m_thread_info; }
     Vector<Entry> const& entries() const { return m_entries; }

Userland/Libraries/LibCoredump/Reader.cpp

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2020, Itamar S. <itamar8910@gmail.com>
+ * Copyright (c) 2022, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -76,10 +77,6 @@ Optional<ByteBuffer> Reader::decompress_coredump(ReadonlyBytes raw_coredump)
     return bytebuffer.release_value();
 }
 
-Reader::~Reader()
-{
-}
-
 Reader::NotesEntryIterator::NotesEntryIterator(const u8* notes_data)
     : m_current(bit_cast<const ELF::Core::NotesEntry*>(notes_data))
     , start(notes_data)

Userland/Libraries/LibCoredump/Reader.h

@@ -40,7 +40,7 @@ class Reader {
 
 public:
     static OwnPtr<Reader> create(StringView);
-    ~Reader();
+    ~Reader() = default;
 
     template<typename Func>
     void for_each_memory_region_info(Func func) const;