libgcc_s: export integer and floating point __aeabi_ symbols

Export all integer and floating point aeabi_ functions defined by
"Run-time ABI for Arm Architecture" from libgcc, excluding aeabi_h2f_alt,
aeabi_f2h_alt and aeabi_d2h_alt, which are not yet implemented by
compiler-rt.

To maintain ABI backward compatibility, convert __aeabi_ floating-point
symbols previously exported from libc to an explicit non-default version.

Remove guessing of vfp/not-vfp version for compiler-rt sources. The vfp
version needs additional runtime logic to select the right implementation
and we don't have it implemented.

MFC after: 1 month
Reviewed by: dim
PR: 271087
Differential Revision: https://reviews.freebsd.org/D50100