Refactor type specific macros using regexes

Replace most of the type specific macros  with the equivalent
type-generic macro using the following sed replacement command below:

sed -ri -e 's/defined TEST_FLOAT/TEST_COND_binary32/' \
        -e 's/ndef TEST_FLOAT/ !TEST_COND_binary32/'  \
        -e 's/def TEST_FLOAT/ TEST_COND_binary32/'    \
        -e 's/defined TEST_DOUBLE/TEST_COND_binary64/'\
        -e 's/ndef TEST_DOUBLE/ !TEST_COND_binary64/' \
        -e 's/def TEST_DOUBLE/ TEST_COND_binary64/'   \
        -e 's/defined TEST_LDOUBLE && //'             \
        -e 's/ifdef TEST_LDOUBLE/if MANT_DIG >= 64/'  \
        -e 's/defined TEST_LDOUBLE/MANT_DIG >= 64/'   \
        -e '/nexttoward_test_data\[\]/,/  };/!s/LDBL_(MIN_EXP|MAX_EXP|MANT_DIG)/\1/g' \
        libm-test.inc

With a little extra manual cleanup to simplify the following case:

#if MANT_DIG >= 64
# if MANT_DIG >= 64
...
# endif
...

Note, TEST_LDOUBLE checks are replaced by MANT_DIG >= 64 excepting
where another property of the type is being tested. And, the final
regex is intended to avoid replacing LDBL_ macro usage within the
nexttoward tests which explicitly take argument 2 as long double.