Re-evaluate usage of addSuppressed

> discussed offline with @NiteshKant ... I think we should re-evaluate our usage of addSuppressed. In the face of static exceptions and addSuppressed may throw if the exception is the same instance this creates potentially undesirable behavior at the benefit of "maybe providing more context".

Originally raised here: https://github.com/servicetalk/servicetalk/pull/131#discussion_r232133741

Start by reading the discussion linked from pull request 131, especially the referenced comment, and inspect the repository's usage of addSuppressed. The issue does not identify affected files, tests, or a decided replacement, so the completed work would first require agreeing on the intended usage and then updating all relevant cases.

Written by the indexing model from the issue text.