VS2017 RC currently enabled project-wide analysis based on ParseAndCheckProject and shows red-squiggly errors based on the results

See vsintegration\src\FSharp.Editor\ProjectDiagnosticAnalyzer.fs

This is wrong, because this method checks using saved files on-disk, not the current contents of buffers. This results in erratic, persistent red-squiggly errors being shown in half-edited unsaved files in the IDE.

We should just disable this feature for now