Replace random data generation with pseudo random

[alzimmermsft]

Description

Changes random data generation logic to generate pseudo random data to reduce git pack file sizes and help future work in sessions records where request and response bodies may be compressed (to help shrink session record sizes).

The following are how .git folder sizes shrunk due to this change:

Blob

Changefeed

Cryptography

NIO

Datalake

Shares

This reduce .git folder sizes from 1258 MB to 688 MB, saving 570 MB each time a full set of session records need to be downloaded.

A follow-up to this change should be an investigation in changing how much data the Cryptography library uses in testing to see if the session record sizes can be shrunk as the request and response bodies are encrypted data streams which won't be able to compress well given encrypted data randomness.

All SDK Contribution checklist:

• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.

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• Title of the pull request is clear and informative.
• There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR. For more information on cleaning up the commits in your PR, see this page.

Testing Guidelines

• Pull request includes test coverage for the included changes.

[azure-sdk]

API change check

API changes are not detected in this pull request.

[kyleknap]

Looks good. I just had one small suggestion. Otherwise 🚢