patch 9.0.1994: inconsistent feature description

Problem:  inconsistent feature description
Solution: delete old mentioned feature sets small and big

The may however still be mentioned for historical reasons. e.g. The
last Amiga built version is for Vim6.2 and is still a big version.

closes: #13273

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: RestorerZ <restorer@mail2k.ru>
diff --git a/runtime/doc/testing.txt b/runtime/doc/testing.txt
index 362f2b9..2d78c0e 100644
--- a/runtime/doc/testing.txt
+++ b/runtime/doc/testing.txt
@@ -21,7 +21,7 @@
 The tests are located in the directory "src/testdir".
 
 There are two types of tests added over time:
-	test20.in		oldest, only for tiny and small builds
+	test20.in		oldest, only for tiny builds
 	test_something.vim	new style tests
 
 						*new-style-testing*