Increase timeout for some test cases in mocha

[xconverge]

Testing to see if this works...

[xconverge]

I am fine if this is merged, but it is certainly interesting... Prior to this, these failures were seen. Now these tests take about ~4759ms

 1) Mode Visual handles as in visual mode Select sentence with leading spaces in visual mode:
     Error: Timeout of 4000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves.
  
  2) Mode Visual handles is in visual mode Select inner sentence with leading spaces in visual mode:
     Error: Timeout of 4000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves.
  
  3) Mode Visual handles is in visual mode Select spaces between sentences in visual mode:
     Error: Timeout of 4000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves.
      at process._tickCallback (internal/process/next_tick.js:103:7)

  4) Motions in Normal Mode Remembers a reverse search from another editor:
     Error: Timeout of 4000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves.
      at process._tickCallback (internal/process/next_tick.js:103:7)

  5) Motions in Normal Mode Shares reverse search history from another editor:
     Error: Timeout of 4000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves.
      at process._tickCallback (internal/process/next_tick.js:103:7)

  6) Motions in Normal Mode Can handle #:
     Error: Timeout of 4000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves.
      at process._tickCallback (internal/process/next_tick.js:103:7)