feat(runtime): improve queue management APIs

[finger563]

Description

• Update wait/sleep event factory APIs to return immediately if the queue already has events in it
• Update event factory clear_events API to copy then empty the queue under lock, then free the memory associated with the pointers in the copy outside of lock to prevent multiple locks/unlocks while clearing the queue which could result in race conditions.

Motivation and Context

How has this been tested?

Screenshots (if appropriate, e.g. schematic, board, console logs, lab pictures):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update
• Software change

Checklist:

• My change requires a change to the documentation.
• I have added / updated the documentation related to this change via either README or WIKI

Software

• I have added tests to cover my changes.
• All new and existing tests passed.
• My code follows the code style of this project.