Revert "AK: Made Strings reversible"

This reverts commit 26e81ad574.

We forgot to consider UTF-8 here. String is UTF-8 and we need to be
careful about things like this.

AK/String.h

@@ -110,13 +110,6 @@ public:
         return m_impl->to_uppercase();
     }
 
-    String reversed() const
-    {
-        if (!m_impl)
-            return String();
-        return m_impl->reversed();
-    }
-
     Vector<String> split_limit(char separator, int limit) const;
     Vector<String> split(char separator) const;
     String substring(int start, int length) const;
@@ -234,6 +227,7 @@ struct Traits<String> : public GenericTraits<String> {
 struct CaseInsensitiveStringTraits : public AK::Traits<String> {
     static unsigned hash(const String& s) { return s.impl() ? s.to_lowercase().impl()->hash() : 0; }
     static bool equals(const String& a, const String& b) { return a.to_lowercase() == b.to_lowercase(); }
+
 };
 
 inline bool operator<(const char* characters, const String& string)
@@ -270,5 +264,5 @@ inline bool operator<=(const char* characters, const String& string)
 
 }
 
-using AK::CaseInsensitiveStringTraits;
 using AK::String;
+using AK::CaseInsensitiveStringTraits;

AK/StringImpl.cpp

@@ -4,7 +4,7 @@
 #include "kmalloc.h"
 
 #ifndef __serenity__
-#    include <new>
+#include <new>
 #endif
 
 //#define DEBUG_STRINGIMPL
@@ -172,19 +172,4 @@ void StringImpl::compute_hash() const
     m_has_hash = true;
 }
 
-NonnullRefPtr<StringImpl> StringImpl::reversed() const
-{
-    if (m_length == 0)
-        return the_empty_stringimpl();
-
-    char* buffer;
-    const char* pos = &m_inline_buffer[m_length - 1];
-    auto new_impl = create_uninitialized(m_length, buffer);
-
-    for (int i = 0; i < m_length; i++)
-        buffer[i] = *pos--;
-
-    return new_impl;
-}
-
 }

AK/StringImpl.h

@@ -1,7 +1,7 @@
 #pragma once
 
-#include <AK/RefCounted.h>
 #include <AK/RefPtr.h>
+#include <AK/RefCounted.h>
 #include <AK/Types.h>
 #include <AK/kmalloc.h>
 
@@ -44,8 +44,6 @@ public:
         return m_hash;
     }
 
-    NonnullRefPtr<StringImpl> reversed() const;
-
 private:
     enum ConstructTheEmptyStringImplTag {
         ConstructTheEmptyStringImpl

AK/Tests/TestString.cpp

@@ -41,7 +41,6 @@ TEST_CASE(compare)
     EXPECT(!("a" >= String("b")));
     EXPECT("a" <= String("a"));
     EXPECT(!("b" <= String("a")));
-    EXPECT(!strcmp(test_string.reversed().characters(), "FEDCBA"));
 }
 
 TEST_CASE(index_access)