[fcl-hash] fprsa and fptlsbigint leak memory

Version tested:_ Lazarus 4.99 (rev main_4_99-4072-ge40c8e7dec) FPC 3.3.1 x86_64-win64-win32/win64_

Attached, you will find two example applications where Heaptrc report memory leaks: memory_leaks.zip

The leaks seem to happen within the fprsa and fptlsbigint units. These units are lower-level than what I'm used to, so I'm not fully confident in my patches. Still, here they are:

fptlsbigint_memory_leak.patch

fprsa_memory_leak.patch

Once the patches are applied, no more memory leaks are reported.