ALL: Clarify bzero related usage

[jpaskhay]

There are some notes and TODOs around bzero usage in the Java and C# repos. Need to investigate and clarify any open questions. Apply any needed changes and/or cleanup comments.

[jgowdy]

This is a non-issue. The purpose of explicit_bzero is to avoid C compilers from determining the call to bzero is useless and optimizing it away. We are accessing glibc at runtime via a dynamic call directly to the bzero function. There is no opportunity for this call to be optimized away as a dynamic call at runtime. I've removed the comments from C# and Java in #300