Make Timeout::Error#exception with multiple arguments not ignore arguments

[jeremyevans]

This makes:

raise(Timeout::Error.new("hello"), "world")

raise a TimeoutError instance with "world" as the message instead
of "hello", for consistency with other Ruby exception classes.

This required some internal changes to keep the tests passing.

Fixes [Bug #17812]

[ioquatix]

This seems okay to me. However it also seems like this was created before #cause was introduced. I am okay with the change, but I also wonder if rewriting an exceptions backtrace and message is really a good idea.

[nobu]

Is the different object needed?

Suggested change

	catch_value = Object.new
	exc.instance_variable_set(:@catch_value, catch_value)
	::Kernel.catch(catch_value) {yield exc}
	exc.instance_variable_set(:@catch_value, exc)
	::Kernel.catch(exc) {yield exc}

[jeremyevans]

I'll try that approach, it would be good to avoid the object allocation.

[jeremyevans]

@ioquatix CI was apparently having issues, with errors like: [TypeError] exception expected, not #<NoMethodError: undefined method current_scheduler for Fiber:Class>. I'm fixed it like this: 25de5e4. If that isn't correct, please push a commit to fix it.