Bug#40657: assertion with out of range variables and traditional sql_mode

test-fixes for 32-bit

mysql-test/t/variables.test:
  Test for 10351 ("Max_Heap_Table_Size cannot be set to 4 gb")
  now throws a warning on 32-bit, as it should. As we're not
  actually interested in the warning but only in whether the
  variable is set to a correct value afterwards, we disable
  warnings for the duration of that test case so we won't have
  to split the test into a 32-bit and a 64-bit flavour for no
  real reason.

mysql-test/t/variables.test

@@ -647,12 +647,14 @@ set @@global.error_count=1;
 # Bug #10351: Setting ulong variable to > MAX_ULONG fails on 32-bit platform
 #
 
+--disable_warnings
 set @@max_heap_table_size= 4294967296;
 select @@max_heap_table_size > 0;
 set global max_heap_table_size= 4294967296;
 select @@max_heap_table_size > 0;
 set @@max_heap_table_size= 4294967296;
 select @@max_heap_table_size > 0;
+--enable_warnings
 
 #
 # Bug #11775 Variable character_set_system does not exist (sometimes)