x86: lab 9 needs to be clarified

[apnorton]

The inlab/postlab sections are unclear as to what students need to have completed for each deadline. I would change this myself, but I'm actually uncertain what the proper interpretation is. (Are they supposed to do 2 topics for the in-lab? Or is it 2 topics total? etc.)

[aaronbloomfield]

For this semester (fall 2015), we'll be flexible in the grading, so any "reasonable" interpretation is valid. I'm going to target this fix for the spring 2016 semester, as I prefer not to make many changes to the labs after they have been released.