fix lowercase* tests labrador

mysql-test/r/lowercase_fs_on.result

 #
 # Bug#20198490 : LOWER_CASE_TABLE_NAMES=0 ON WINDOWS LEADS TO PROBLEMS
 #
+FOUND /\[ERROR\] The server option \'lower_case_table_names\' is configured to use case sensitive table names/ in my_restart.err

mysql-test/r/lowercase_table4.result

@@ -4,6 +4,9 @@
 #
 CREATE DATABASE XY;
 USE XY;
+set @old_table_open_cache=@@table_open_cache;
+set global table_open_cache = 512;
+set global table_open_cache = @old_table_open_cache;
 DROP DATABASE XY;
 USE TEST;
 #

mysql-test/t/lowercase_fs_on.test

@@ -26,7 +26,7 @@ let SEARCH_FILE= $MYSQLTEST_VARDIR/log/my_restart.err;
 --exec $MYSQLD_CMD --lower_case_table_names=0 > $SEARCH_FILE  2>&1
 
 #Search for the error messege in the server error log.
-let SEARCH_PATTERN= \[ERROR\] The server option \'lower_case_table_names\' is configured to use case sensitive table names but the data directory is on a case-insensitive file system which is an unsupported combination\. Please consider either using a case sensitive file system for your data directory or switching to a case-insensitive table name mode\.;
+let SEARCH_PATTERN= \[ERROR\] The server option \'lower_case_table_names\' is configured to use case sensitive table names;
 --source include/search_pattern_in_file.inc
 
 #Restart the server

mysql-test/t/lowercase_table4.test

@@ -8,6 +8,8 @@
 
 CREATE DATABASE XY;
 USE XY;
+set @old_table_open_cache=@@table_open_cache;
+set global table_open_cache = 512;
 
 #
 # Logs are disabled, since the number of creates tables
@@ -52,6 +54,7 @@ eval SELECT * FROM XY.T_$tcs LIMIT 1;
 
 --enable_query_log
 --enable_result_log
+set global table_open_cache = @old_table_open_cache;
 DROP DATABASE XY;
 USE TEST;
 

sql/mysqld.cc

@@ -4556,23 +4556,12 @@ static int init_common_variables()
   {
     if (lower_case_table_names_used)
     {
-#if MYSQL_VERSION_ID < 100100
-      if (global_system_variables.log_warnings)
-        sql_print_warning("You have forced lower_case_table_names to 0 through "
-                          "a command-line option, even though your file system "
-                          "'%s' is case insensitive.  This means that you can "
-                          "corrupt your tables if you access them using names "
-                          "with different letter case. You should consider "
-                          "changing lower_case_table_names to 1 or 2",
-                          mysql_real_data_home);
-#else
       sql_print_error("The server option 'lower_case_table_names' is "
                       "configured to use case sensitive table names but the "
                       "data directory resides on a case-insensitive file system. "
                       "Please use a case sensitive file system for your data "
                       "directory or switch to a case-insensitive table name "
                       "mode.");
-#endif
       return 1;
     }
     else