patch 8.1.0599: without the +eval feature the indent tests don't work

Problem:    Without the +eval feature the indent tests don't work.
Solution:   Skip the body of the tests.

runtime/indent/testdir/runtest.vim

@@ -2,6 +2,9 @@
 "
 " Current directory must be runtime/indent.
 
+" Only do this with the +eval feature
+if 1
+
 set nocp
 filetype indent on
 set nowrapscan
@@ -116,4 +119,7 @@ for fname in glob('testdir/*.in', 1, 1)
   endif
 endfor
 
+" Matching "if 1" at the start.
+endif
+
 qall!