Changes the one regexp in PyParse capable of making the re module blow the C
stack when passed unreasonable <0.9 wink> program text.  Jeremy Hylton
provoked this with a program of the form:

x = (1,
     2,
... # 9997 lines deleted here
     10000,
)

Programs "like this" will no longer (no matter how many lines they contain)
trigger re death.  OTOH, you can now make another class of unreasonable
program that will take much longer to parse.