AK: Remove unused `rehash_for_collision`

AK/HashFunctions.h

@@ -19,20 +19,6 @@ constexpr unsigned int_hash(u32 key)
     return key;
 }
 
-constexpr unsigned rehash_for_collision(u32 key)
-{
-    unsigned const magic = 0xBA5EDB01;
-    if (key == magic)
-        return 0u;
-    if (key == 0u)
-        key = magic;
-
-    key ^= key << 13;
-    key ^= key >> 17;
-    key ^= key << 5;
-    return key;
-}
-
 constexpr unsigned pair_int_hash(u32 key1, u32 key2)
 {
     return int_hash((int_hash(key1) * 209) ^ (int_hash(key2 * 413)));

Tests/AK/TestHashFunctions.cpp

@@ -15,13 +15,6 @@ TEST_CASE(int_hash)
     static_assert(int_hash(0) == 1177991625u);
 }
 
-TEST_CASE(rehash_for_collision)
-{
-    static_assert(rehash_for_collision(666) == 171644115u);
-    static_assert(rehash_for_collision(0) == 1189591134u);
-    static_assert(rehash_for_collision(0xBA5EDB01) == 0u);
-}
-
 TEST_CASE(pair_int_hash)
 {
     static_assert(pair_int_hash(42, 17) == 339337046u);