MDEV-10526: Add binary string support to bitwise operators

Bitwise operators (&, |, ^, ~, <<, >>) previously cast all
arguments to BIGINT, silently truncating values wider than
64 bits. This broke operations on BINARY, VARBINARY, BLOB,
INET6, and UUID columns.

Introduces binary_mode detection in fix_length_and_dec().
When any non-literal argument has STRING_RESULT with binary
charset, operators switch to byte-by-byte processing via
a new Handler_str subclass, returning LONGBLOB of the same
length as the input.

Bare hex literals (x'FF', 0xFF) and bit literals (b'1010')
retain integer mode for backward compatibility.

Existing int/decimal handler classes for Item_func_bit_or
and Item_func_bit_and are moved from item_cmpfunc.cc to
item_func.cc for consistency.

New error codes:
  ER_INVALID_BITWISE_OPERANDS_SIZE
  ER_INVALID_BITWISE_AGGREGATE_OPERANDS_SIZE

Aggregate function support (BIT_AND/BIT_OR/BIT_XOR) to
follow in a subsequent commit.

Closes: MDEV-10526

Author: kjarir

sql/item_cmpfunc.cc

@@ -4920,74 +4920,6 @@ void Item_func_in::mark_as_condition_AND_part(TABLE_LIST *embedding)
 }
 
 
-class Func_handler_bit_or_int_to_ulonglong:
-        public Item_handled_func::Handler_ulonglong
-{
-public:
-  Longlong_null to_longlong_null(Item_handled_func *item) const override
-  {
-    DBUG_ASSERT(item->fixed());
-    Longlong_null a= item->arguments()[0]->to_longlong_null();
-    return a.is_null() ? a : a | item->arguments()[1]->to_longlong_null();
-  }
-};
-
-
-class Func_handler_bit_or_dec_to_ulonglong:
-        public Item_handled_func::Handler_ulonglong
-{
-public:
-  Longlong_null to_longlong_null(Item_handled_func *item) const override
-  {
-    DBUG_ASSERT(item->fixed());
-    VDec a(item->arguments()[0]);
-    return a.is_null() ? Longlong_null() :
-      a.to_xlonglong_null() | VDec(item->arguments()[1]).to_xlonglong_null();
-  }
-};
-
-
-bool Item_func_bit_or::fix_length_and_dec(THD *thd)
-{
-  static Func_handler_bit_or_int_to_ulonglong ha_int_to_ull;
-  static Func_handler_bit_or_dec_to_ulonglong ha_dec_to_ull;
-  return fix_length_and_dec_op2_std(&ha_int_to_ull, &ha_dec_to_ull);
-}
-
-
-class Func_handler_bit_and_int_to_ulonglong:
-        public Item_handled_func::Handler_ulonglong
-{
-public:
-  Longlong_null to_longlong_null(Item_handled_func *item) const override
-  {
-    DBUG_ASSERT(item->fixed());
-    Longlong_null a= item->arguments()[0]->to_longlong_null();
-    return a.is_null() ? a : a & item->arguments()[1]->to_longlong_null();
-  }
-};
-
-
-class Func_handler_bit_and_dec_to_ulonglong:
-        public Item_handled_func::Handler_ulonglong
-{
-public:
-  Longlong_null to_longlong_null(Item_handled_func *item) const override
-  {
-    DBUG_ASSERT(item->fixed());
-    VDec a(item->arguments()[0]);
-    return a.is_null() ?  Longlong_null() :
-      a.to_xlonglong_null() & VDec(item->arguments()[1]).to_xlonglong_null();
-  }
-};
-
-
-bool Item_func_bit_and::fix_length_and_dec(THD *thd)
-{
-  static Func_handler_bit_and_int_to_ulonglong ha_int_to_ull;
-  static Func_handler_bit_and_dec_to_ulonglong ha_dec_to_ull;
-  return fix_length_and_dec_op2_std(&ha_int_to_ull, &ha_dec_to_ull);
-}
 
 Item_cond::Item_cond(THD *thd, Item_cond *item)
   :Item_bool_func(thd, item),