Simplify replacement code for strtof.
strtof() is in C99 and all targeted systems have it. We can remove the
configure probe and some dead code, but we still need replacement code
for a couple of systems that have known buggy implementations selected
via platform template.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/152683.
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