math: Add new exp10 implementation

math: Add new exp10 implementation

New implementation is based on the existing exp/exp2, with different
reduction constants and polynomial. Worst-case error in round-to-
nearest is 0.513 ULP.

The exp/exp2 shared table is reused for exp10 - .rodata size of
e_exp_data increases by 64 bytes.

As for exp/exp2, targets with single-instruction rounding/conversion
intrinsics can use them by toggling TOINT_INTRINSICS=1 and adding the
necessary code to their math_private.h.

Improvements on Neoverse V1 compared to current GLIBC master:
exp10 thruput: 3.3x in [-0x1.439b746e36b52p+8 0x1.34413509f79ffp+8]
exp10 latency: 1.8x in [-0x1.439b746e36b52p+8 0x1.34413509f79ffp+8]

Tested on:
    aarch64-linux-gnu (TOINT_INTRINSICS, fma contraction) and
    x86_64-linux-gnu (!TOINT_INTRINSICS, no fma contraction)

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>