Merge 10.3 into 10.4

In main.index_merge_myisam we remove the test that was added in
commit a2d24def8c because
it duplicates the test case that was added in
commit 5af12e4635.

mysql-test/lib/My/Tee.pm

@@ -10,7 +10,7 @@ sub PUSHED
   open($copyfh, '>', "$::opt_vardir/log/stdout.log")
     or die "open(>$::opt_vardir/log/stdout.log): $!"
       unless $copyfh;
- bless { }, shift;
+  bless { }, shift;
 }
 
 sub WRITE