wasthon — _decimal vs Brython's pure-Python `decimal`

Comparing CPython's Modules/_decimal/_decimal.c + libmpdec via WASM against Brython's Lib/decimal.py (pure-Python _pydecimal).

Operation	wasthon ms/call	Brython ms/call	Speedup	Result (wasthon / Brython)

wasthon — _decimal vs Brython's pure-Python decimal