patch 8.2.0183: tests fail when the float feature is disabled

Problem:    Tests fail when the float feature is disabled.
Solution:   Skip tests that don't work without float support.
diff --git a/src/testdir/test_expr.vim b/src/testdir/test_expr.vim
index eb51cd6..bd9caca 100644
--- a/src/testdir/test_expr.vim
+++ b/src/testdir/test_expr.vim
@@ -369,7 +369,9 @@
   call assert_fails('echo printf("%d", [])', 'E745:')
   call assert_fails('echo printf("%d", 1, 2)', 'E767:')
   call assert_fails('echo printf("%*d", 1)', 'E766:')
-  call assert_fails('echo printf("%d", 1.2)', 'E805:')
+  if has('float')
+    call assert_fails('echo printf("%d", 1.2)', 'E805:')
+  endif
 endfunc
 
 function Test_max_min_errors()