[clang-format] fix conflict between FormatStyle::BWACS_MultiLine and BeforeCatch/BeforeElse

Summary:
Found a bug introduced with BraceWrappingFlags AfterControlStatement MultiLine. This feature conflicts with the existing BeforeCatch and BeforeElse flags.

For example, our team uses BeforeElse.

if (foo ||
    bar) {
  doSomething();
}
else {
  doSomethingElse();
}

If we enable MultiLine (which we'd really love to do) we expect it to work like this:

if (foo ||
    bar)
{
  doSomething();
}
else {
  doSomethingElse();
}

What we actually get is:

if (foo ||
    bar)
{
  doSomething();
}
else
{
  doSomethingElse();
}

Reviewers: MyDeveloperDay, Bouska, mitchell-stellar

Patch by: pastey

Subscribers: Bouska, cfe-commits

Tags: clang

Differential Revision: https://reviews.llvm.org/D71939