Summary: clang-format would previously fail to detect that an arrow functions parameter block is not an expression, and thus insert whitespace around the `|` and `&` type operators in it.

Reviewers: djasper

Subscribers: klimek, cfe-commits

Differential Revision: https://reviews.llvm.org/D36147

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@309707 91177308-0d34-0410-b5e6-96231b3b80d8