21.string.rfind.cpp test fail reason

[Farid Zaripov]

  The problem in 21.string.rfind.cpp test is invoking
string::rfind(const value_type* ptr, size_type off = npos, size_type
count)
with count == string::max_size() + 1 (21.string.rfind.cpp lines
413-416).
The method throws length_error() exception (line 756 file string.cc) but
test
not expected any exceptions.

Farid.