Improve fixit for comparison operator on lhs of bitwise operator.

Before:
test.cc:2:18: note: place parentheses around the == expression to silence this warning
  if (0 == flags & 0xdd)
                 ^
                   (   )

Now:
test.cc:2:18: note: place parentheses around the == expression to silence this warning
  if (0 == flags & 0xdd)
                 ^
      (         )

llvm-svn: 157897