throw ArgumentOutOfRangeException when table key is too long (> 255)

[bollhals]

Proposed Changes

As brought up in #845, there was a bug that if a key of a dictionary was longer than 255, it wrote the overflowed byte value and the full byte array. The reader on the other side though was only reading the number of bytes (the overflowed one) and then the followed reads were then off.

Types of Changes

• Bug fix (non-breaking change which fixes issue #NNNN)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause an observable behavior change in existing systems)
• Documentation improvements (corrections, new content, etc)
• Cosmetic change (whitespace, formatting, etc)

Checklist

• I have read the CONTRIBUTING.md document
• I have signed the CA (see https://cla.pivotal.io/sign/rabbitmq)
• All tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)
• Any dependent changes have been merged and published in related repositories