Add format to stdlib test suite (#1926)
Add format to stdlib test suite (#1926)

Noticed that the format tests didn't run
as part of the stdlib test suite.

Related: #1920
Perelandric/ponyc,Perelandric/ponyc,jemc/ponyc,sgebbie/ponyc,Theodus/ponyc,Perelandric/ponyc,dipinhora/ponyc,Praetonus/ponyc,cquinn/ponyc,boemmels/ponyc,kulibali/ponyc,mkfifo/ponyc,Theodus/ponyc,kulibali/ponyc,kulibali/ponyc,boemmels/ponyc,Perelandric/ponyc,jemc/ponyc,boemmels/ponyc,mkfifo/ponyc,boemmels/ponyc,sgebbie/ponyc,CausalityLtd/ponyc,dipinhora/ponyc,ponylang/ponyc,Praetonus/ponyc,mkfifo/ponyc,Praetonus/ponyc,sgebbie/ponyc,boemmels/ponyc,Praetonus/ponyc,mkfifo/ponyc,kulibali/ponyc,cquinn/ponyc,Theodus/ponyc,Theodus/ponyc,mkfifo/ponyc,cquinn/ponyc,sgebbie/ponyc,jemc/ponyc,ponylang/ponyc,sgebbie/ponyc,ponylang/ponyc,Theodus/ponyc,cquinn/ponyc,CausalityLtd/ponyc,CausalityLtd/ponyc,dipinhora/ponyc,Perelandric/ponyc