patch 8.2.0502: Vim9: some code is not tested

Problem:    Vim9: some code is not tested.
Solution:   Add more tests.  Fix uncovered problems.
diff --git a/src/testdir/test_vim9_disassemble.vim b/src/testdir/test_vim9_disassemble.vim
index 95cd289..36c098c 100644
--- a/src/testdir/test_vim9_disassemble.vim
+++ b/src/testdir/test_vim9_disassemble.vim
@@ -809,6 +809,8 @@
   let cases = [
         \ ['"xx" == "yy"', false],
         \ ['"aa" == "aa"', true],
+        \ ['has("eval") ? true : false', true],
+        \ ['has("asdf") ? true : false', false],
         \ ]
 
   let nr = 1