test(logger): test logger does not format objects as expected

[Hweinstock]

Problem

The test logger does not format additional arguements into the logs in the same way as ToolkitLogger. Ex. getLogger().debug('here is the obj: %O', obj) will produce two LogEntries one with "here is the obj: %O" and one with the object itself.

This is problematic because it causes confusion (see: https://github.com/aws/aws-toolkit-vscode/pull/5895#discussion_r1832979093) and it also can cause assertLogsContain to throw an error since there is now a non-string/error entry in the log entry list (see: https://github.com/aws/aws-toolkit-vscode/blob/338ea67f2ba0294fc535a9a949fd1cdaeaa96d98/packages/core/src/test/globalSetup.test.ts#L171-L185).

Solution

• Have test logger inherit from BaseLogger to minimize implementation dupe.
• If we see a string, format it with extra inputs before pushing it into entries.
• Add tests for the testLogger.
• Adjust existing tests that relied on this behavior.
• If on web, we simply concat the strings to avoid reimplementing util.format: https://github.com/nodejs/node/blob/3178a762d6a2b1a37b74f02266eea0f3d86603be/lib/internal/util/inspect.js#L2191-L2315

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License: I confirm that my contribution is made under the terms of the Apache 2.0 license.