Optimise BinaryConverter's reflection object creation. (#1177)
Optimise BinaryConverter's reflection object creation. (#1177)

Make the test for a type being S.D.L.Binary a single test as Binary is
a sealed class and therefore there's no need to test bases.

Make the stored ReflectionObject static, reducing size and repeated
allocations if BinaryConverter is explicitly created by the user.
bfriesen/Newtonsoft.Json,oxwanawxo/Newtonsoft.Json,PKRoma/Newtonsoft.Json,jkorell/Newtonsoft.Json,skarllot/Newtonsoft.Json,JamesNK/Newtonsoft.Json,ze-pequeno/Newtonsoft.Json,benaadams/Newtonsoft.Json,brjohnstmsft/Newtonsoft.Json,ValtoLibraries/Newtonsoft.Json,TylerBrinkley/Newtonsoft.Json