Renamed autogenerated search tests to distinguish them from the
autogenerated startsWith tests.
Added startsWith tests. Generated by:

  ../src/re_gen/forms 2 | ../src/re_gen/inst abc. '' '' '+' '*' \
    '?' '+?' '*?' '??' '{0,1}' '{2}' '{1,2}' '{2,}' '{0,1}?' '{2}?' \
    '{1,2}?' '{2,}?' | ./pat2swith.py `../src/re_gen/debruijn 3 abc`