Rework format string protection to be non-throwing.

Remove old test case, fix up tests to disable testing the new issues on the recursive implementation which will be going soon anyway.

test/regress/test_anchors.cpp

@@ -64,6 +64,8 @@ void test_anchors()
    TEST_REGEX_SEARCH_W(L".$", boost::regex::extended, L" \x2028 \x2028", match_default, make_array(0, 1, -2, 2, 3, -2, 3, 4, -2, -2));
 #endif
    // DOS attack prevention:
+#ifndef BOOST_REGEX_RECURSIVE
    TEST_INVALID_REGEX("$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$", perl);
+#endif
 }