patch 9.1.0794: tests: tests may fail on Windows environment

Problem:  tests: tests may fail on Windows environment
Solution: use shellcmdflag=/D to skip executing autorun from
          the registry (Milly)

closes: #15900

Signed-off-by: Milly <milly.ca@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_terminal2.vim b/src/testdir/test_terminal2.vim
index 05b228e..166b179 100644
--- a/src/testdir/test_terminal2.vim
+++ b/src/testdir/test_terminal2.vim
@@ -450,7 +450,7 @@
   for c in contents
     call writefile(c, 'Xdntfile', 'D')
     if has('win32')
-      term cmd /c type Xdntfile
+      term cmd /D /c type Xdntfile
     else
       term cat Xdntfile
     endif
@@ -465,7 +465,7 @@
 
 func GetDummyCmd()
   if has('win32')
-    return 'cmd /c ""'
+    return 'cmd /D /c ""'
   else
     CheckExecutable false
     return 'false'