Fix layout of lambda captures.

Before:
 int c = [ &, &a, a]{
   [ =, c, &d]{
     return b++;
   }();
 }();

After:
 int c = [&, &a, a] {
   [=, c, &d] {
     return b++;
   }();
 }();

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@189924 91177308-0d34-0410-b5e6-96231b3b80d8