[test] Add Object Stream Formatter to work with test utility HexPrinter

Understanding the contents of a stream of serialized objects is difficult
due to the streaming format and immediate nesting of objects.
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ObjectStreamPrinter is a Formatter plugin to the test library HexPrinter.
It converts a binary ObjectStream into a textual form by parsing
the header, typecodes, and interpreting the stream contents.

StreamDump is a test utility to pass the contents of a file to the HexPrinter utility. The format of the file is guessed from the encoding and initial bytes.
ASN.1 and serialized object streams are supported.