Use InvariantCulture when running FSI scripts in tests

[kerams]

This addresses failures where tests are culture-dependent, like here, where wrong column type is inferred because of decimal separator settings.

  Message:
System.ArgumentException : Provided label column 'median_house_value' was of type String, but only type Single is allowed.

  Stack Trace:
DependencyManagerInteractiveTests.getValue(FSharpResult`2 value, FSharpDiagnostic[] errors) line 34
DependencyManagerInteractiveTests.Use Dependency Manager to restore packages with native dependencies, build and run script that depends on the results() line 356
RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor)
MethodInvoker.Invoke(Object obj, IntPtr* args, BindingFlags invokeAttr)