Issue #21881: Be more tolerant in test_tcl to not parsable by float() NaN

representations (on mips and m68k platforms).

diff --cc Lib/test/test_tcl.py
index e5b17a1da6285c3b5989b0afe015ccc443e401ad,cb86a7390ee8951f96a0fa8faf70b1726b70158d..9c5d97452bf17c2e947a3ceb6e9fe99fd8a28397
--- 1/Lib/test/test_tcl.py
--- 2/Lib/test/test_tcl.py
+++ b/Lib/test/test_tcl.py
@@@ -458,10 -456,9 +458,10 @@@ class TclTest(unittest.TestCase)
              check(f, f, eq=float_eq)
          check(float('inf'), 'Inf', eq=float_eq)
          check(-float('inf'), '-Inf', eq=float_eq)
-         check(float('nan'), 'NaN', eq=nan_eq)
+         check(float('nan'), 'nan', eq=starts_with)
          check((), '')
          check((1, (2,), (3, 4), '5 6', ()), '1 2 {3 4} {5 6} {}')
 +        check([1, [2,], [3, 4], '5 6', []], '1 2 {3 4} {5 6} {}')
  
      def test_splitlist(self):
          splitlist = self.interp.tk.splitlist