patch 9.1.1511: tests: two edit tests change v:testing from 1 to 0

Problem:  tests: two edit tests change v:testing from 1 to 0.
Solution: Don't change v:testing in these two tests, since it's already
          set to 1 in runtest.vim (zeertzjq).

closes: #17660

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/runtest.vim b/src/testdir/runtest.vim
index f03fe44..b1ffd19 100644
--- a/src/testdir/runtest.vim
+++ b/src/testdir/runtest.vim
@@ -180,6 +180,7 @@
 
 
 " Prepare for calling test_garbagecollect_now().
+" Also avois some delays in Insert mode completion.
 let v:testing = 1
 
 " By default, copy each buffer line into allocated memory, so that valgrind can