Separate Test Runner from Mock Server and Test Project

[runningcode]

This PR separates the test runner from the Mock Server and the Gradle Project.

This fixes a few things:

• The new runner avoids using withPluginClasspath(). Using that method can be dangerous as it pollutes the classpath of the build under test with the test code and outer build.
• Allow the test projects to be built dynamically using code to allow dyanmic version testing.
• This also ensures that the MockServer is shut down even if the test fails.
• Fixes broken github PR event tests.
• Tests the code using logging output instead of writing to a file and deserializing it which should fix the broken tests in the shadow PR.

[runningcode]

• Remove usages of kotlinx serialization from test code #466
• Separate Test Runner from Mock Server and Test Project #465 👈 (View in Graphite)
• Remove simple-agp-7.2.0 project as it is identical to simple #462
• main

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