Effectively renamed tokenize_tests.py to have a txt extension instead.

This file isn't meant to be executed, it's data input for test_tokenize.py.
The problem with the .py extension is that it uses "non-standard"
indentation, and it's good to test that, but reindent.py keeps wanting
to fix it.  But fixing the indentation causes the expected-output file to
change, since exact line and column numbers are part of the
tokenize.tokenize() output getting tested.

Lib/test/tokenize_tests.txt

@@ -0,0 +1,175 @@
+# Tests for the 'tokenize' module.
+# Large bits stolen from test_grammar.py. 
+
+# Comments
+"#"
+#'
+#"
+#\
+       #
+    # abc
+'''#
+#'''
+
+x = 1  #
+
+# Balancing continuation
+
+a = (3, 4,
+  5, 6)
+y = [3, 4,
+  5]
+z = {'a':5,
+  'b':6}
+x = (len(`y`) + 5*x - a[
+   3 ]
+   - x + len({
+   }
+    )
+  )
+
+# Backslash means line continuation:
+x = 1 \
++ 1
+
+# Backslash does not means continuation in comments :\
+x = 0
+
+# Ordinary integers
+0xff <> 255
+0377 <> 255
+2147483647   != 017777777777
+-2147483647-1 != 020000000000
+037777777777 != -1
+0xffffffff != -1
+
+# Long integers
+x = 0L
+x = 0l
+x = 0xffffffffffffffffL
+x = 0xffffffffffffffffl
+x = 077777777777777777L
+x = 077777777777777777l
+x = 123456789012345678901234567890L
+x = 123456789012345678901234567890l
+
+# Floating-point numbers
+x = 3.14
+x = 314.
+x = 0.314
+# XXX x = 000.314
+x = .314
+x = 3e14
+x = 3E14
+x = 3e-14
+x = 3e+14
+x = 3.e14
+x = .3e14
+x = 3.1e4
+
+# String literals
+x = ''; y = "";
+x = '\''; y = "'";
+x = '"'; y = "\"";
+x = "doesn't \"shrink\" does it"
+y = 'doesn\'t "shrink" does it'
+x = "does \"shrink\" doesn't it"
+y = 'does "shrink" doesn\'t it'
+x = """
+The "quick"
+brown fox
+jumps over
+the 'lazy' dog.
+"""
+y = '\nThe "quick"\nbrown fox\njumps over\nthe \'lazy\' dog.\n'
+y = '''
+The "quick"
+brown fox
+jumps over
+the 'lazy' dog.
+''';
+y = "\n\
+The \"quick\"\n\
+brown fox\n\
+jumps over\n\
+the 'lazy' dog.\n\
+";
+y = '\n\
+The \"quick\"\n\
+brown fox\n\
+jumps over\n\
+the \'lazy\' dog.\n\
+';
+x = r'\\' + R'\\'
+x = r'\'' + ''
+y = r'''
+foo bar \\
+baz''' + R'''
+foo'''
+y = r"""foo
+bar \\ baz
+""" + R'''spam
+'''
+x = u'abc' + U'ABC'
+y = u"abc" + U"ABC"
+x = ur'abc' + Ur'ABC' + uR'ABC' + UR'ABC'
+y = ur"abc" + Ur"ABC" + uR"ABC" + UR"ABC"
+x = ur'\\' + UR'\\'
+x = ur'\'' + ''
+y = ur'''
+foo bar \\
+baz''' + UR'''
+foo'''
+y = Ur"""foo
+bar \\ baz
+""" + uR'''spam
+'''
+
+# Indentation
+if 1:
+    x = 2
+if 1:
+        x = 2
+if 1:
+    while 0:
+     if 0:
+           x = 2
+     x = 2
+if 0:
+  if 2:
+   while 0:
+        if 1:
+          x = 2
+
+# Operators
+
+def d22(a, b, c=1, d=2): pass
+def d01v(a=1, *restt, **restd): pass
+
+(x, y) <> ({'a':1}, {'b':2})
+
+# comparison
+if 1 < 1 > 1 == 1 >= 1 <= 1 <> 1 != 1 in 1 not in 1 is 1 is not 1: pass
+
+# binary
+x = 1 & 1
+x = 1 ^ 1
+x = 1 | 1
+
+# shift
+x = 1 << 1 >> 1
+
+# additive
+x = 1 - 1 + 1 - 1 + 1
+
+# multiplicative
+x = 1 / 1 * 1 % 1
+
+# unary
+x = ~1 ^ 1 & 1 | 1 & 1 ^ -1
+x = -1*1/1 + 1*1 - ---1*1
+
+# selector
+import sys, time
+x = sys.modules['time'].time()
+