Revert patch for Bug #12595, it causes the sql_mode test to fail.

mysql-test/r/select.result:
  Update results
mysql-test/t/select.test:
  Remove regression test
sql/item_cmpfunc.cc:
  Revert patch for checking length of ESCAPE, it is not correct.

mysql-test/r/select.result

@@ -2756,14 +2756,3 @@ DROP TABLE t1,t2;
 select x'10' + 0, X'10' + 0, b'10' + 0, B'10' + 0;
 x'10' + 0	X'10' + 0	b'10' + 0	B'10' + 0
 16	16	2	2
-CREATE TABLE BUG_12595(a varchar(100));
-INSERT INTO BUG_12595 VALUES ('hakan%'), ('hakank'), ("ha%an");
-SELECT * FROM BUG_12595 WHERE a LIKE 'hakan*%' ESCAPE '*';
-a
-hakan%
-SELECT * FROM BUG_12595 WHERE a LIKE 'hakan**%' ESCAPE '**';
-ERROR HY000: Incorrect arguments to ESCAPE
-SELECT * FROM BUG_12595 WHERE a LIKE 'ha%%an' ESCAPE '%';
-a
-ha%an
-DROP TABLE BUG_12595;

mysql-test/t/select.test

@@ -2348,14 +2348,3 @@ DROP TABLE t1,t2;
 #
 
 select x'10' + 0, X'10' + 0, b'10' + 0, B'10' + 0;
-
-#
-# BUG #12595
-#
-CREATE TABLE BUG_12595(a varchar(100));
-INSERT INTO BUG_12595 VALUES ('hakan%'), ('hakank'), ("ha%an");
-SELECT * FROM BUG_12595 WHERE a LIKE 'hakan*%' ESCAPE '*';
--- error 1210
-SELECT * FROM BUG_12595 WHERE a LIKE 'hakan**%' ESCAPE '**';
-SELECT * FROM BUG_12595 WHERE a LIKE 'ha%%an' ESCAPE '%';
-DROP TABLE BUG_12595;

sql/item_cmpfunc.cc

@@ -2792,12 +2792,6 @@ bool Item_func_like::fix_fields(THD *thd, Item **ref)
   {
     /* If we are on execution stage */
     String *escape_str= escape_item->val_str(&tmp_value1);
-    /* ESCAPE must be 1 char in length.*/
-    if (escape_str && escape_str->numchars() != 1)
-    {
-      my_error(ER_WRONG_ARGUMENTS,MYF(0),"ESCAPE");
-      return TRUE;
-    }
     escape= escape_str ? *(escape_str->ptr()) : '\\';
 
     /*