patch 8.2.1512: failure after trinary expression fails

Problem:    Failure after trinary expression fails.
Solution:   Restore eval_flags. (Yasuhiro Matsumoto, closes #6776)
diff --git a/src/testdir/test_vim9_expr.vim b/src/testdir/test_vim9_expr.vim
index d9e823a..4ff0fd7 100644
--- a/src/testdir/test_vim9_expr.vim
+++ b/src/testdir/test_vim9_expr.vim
@@ -114,6 +114,27 @@
       let var = v:true ? 1 :2
   END
   CheckScriptFailure(lines, 'E1004:', 2)
+
+  # check after failure eval_flags is reset
+  lines =<< trim END
+      vim9script
+      try
+        call eval('0 ? 1: 2')
+      catch
+      endtry
+      assert_equal(v:true, eval(string(v:true)))
+  END
+  CheckScriptSuccess(lines)
+
+  lines =<< trim END
+      vim9script
+      try
+        call eval('0 ? 1 :2')
+      catch
+      endtry
+      assert_equal(v:true, eval(string(v:true)))
+  END
+  CheckScriptSuccess(lines)
 enddef
 
 func Test_expr1_fails()