When testing JIT code, it is useful to be able to access the
generated JIT source. Previously this is done by spying on the
global `Function` object, to capture the code when it is being
evaluated. This is problematic because you can only capture
the body of the function, and not the arguments, which messes
up line and column positions for source mapping for instance.
Now the code that generates and then evaluates JIT code is
wrapped in a `JitEvaluator` class, making it possible to provide
a mock implementation that can capture the generated source of
the function passed to `executeFunction(fn: Function, args: any[])`.
PR Close#28055
54ca24b47d