[Truffle] Untagged some passing Float specs.
[Truffle] Untagged passing String specs.
[Truffle] Properly interpolate strings referencing objects with private to_s implementations.
[Truffle] Fix String interpolation when the referenced object's 'to_s' doesn't return a String.
[Truffle] Get rid of some nulls just to be safe.
There seems to be no point in manually inlining a method here.
[Truffle] Implemented enough of Encoding.list to get Encoding#to_s specs passing.
[Truffle] Added a helper for creating a RubyString from a ByteList.
[Truffle] Store the encoding name in a convenient format.
[Truffle] Implemented Encoding#to_s.
[Truffle] Initial implementation of Encoding#inspect.
[Truffle] Last of the match specs.
Commented out flaky spec that also wasn't testing what it was supposed to.

See #2299: 'Improve FFI::Function can wrap a blocking function spec' for details.