patch 8.2.0986: MS-Windows: functions test fails

Problem:    MS-Windows: functions test fails.
Solution:   Only simplify ///path on Unix.
diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index aad5a8c..d9f8b9a 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -464,8 +464,10 @@
   call assert_equal('/',           simplify('/..'))
   call assert_equal('/...',        simplify('/...'))
   call assert_equal('//path',      simplify('//path'))
-  call assert_equal('/path',       simplify('///path'))
-  call assert_equal('/path',       simplify('////path'))
+  if has('unix')
+    call assert_equal('/path',       simplify('///path'))
+    call assert_equal('/path',       simplify('////path'))
+  endif
 
   call assert_equal('./dir/file',  './dir/file'->simplify())
   call assert_equal('./dir/file',  simplify('.///dir//file'))