Fix race condition in Microsoft.Extensions.Configuration test

[jkotas]

Fixes #109904

[Copilot]

Pull Request Overview

This PR fixes a race condition in Microsoft.Extensions.Configuration tests where variable initialization and null checks were creating potential null reference exceptions during concurrent operations. The fix removes unnecessary null checks and initialization tracking variables, simplifying the code to use a do-while loop pattern that guarantees at least one execution.

Key changes:

• Removed redundant null initialization and tracking variables
• Replaced while loops with do-while loops to ensure variables are always assigned before assertions
• Removed temporary instrumentation code that was added for debugging the race condition

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
ConfigurationTests.cs	Simplified loop logic by removing optionsInitialized tracking and null initialization, using do-while pattern
EnvironmentVariablesTest.cs	Removed debugging instrumentation code and applied same race condition fix with do-while pattern

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[tarekgh]

Thanks for fixing the issue and knowing the underlying reason causing the test failure!