Add warning group -Woverloaded-shift-op-parentheses to -Wparentheses. This

Add warning group -Woverloaded-shift-op-parentheses to -Wparentheses.  This
will fire on code such as:

  cout << x == 0;

which the compiler will intrepret as

  (cout << x) == 0;

This warning comes with two fixits attached to notes, one for parentheses to
silence the warning, and another to evaluate the comparison first.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179662 91177308-0d34-0410-b5e6-96231b3b80d8