[PATCH 0/2] string: Speed up comparison test data initialization

Patch 1 updates strcmp and strncmp, including the wide-character tests
which reuse the same sources. Patch 2 updates strcasecmp and
strncasecmp while preserving locale-dependent case conversion.

On alpha-linux-gnu, a first-run comparison showed approximate speedups
of 57x for test-strcmp, more than 46x for test-strncmp, 6.7x for
test-strcasecmp, and more than 12x for test-strncasecmp. The unpatched
strncmp and strncasecmp tests reached the 50-minute timeout, while all
affected tests pass with this series.

Magnus Lindholm (2):
string: Speed up strcmp test data initialization
string: Speed up strcasecmp test data initialization