clang-format: [JS] Do not break before 'as'.

Summary:
'as' is a pseudo operator, so automatic semicolon insertion kicks in and the
code fails to part.

Reviewers: djasper

Subscribers: klimek

Differential Revision: http://reviews.llvm.org/D21576

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@273422 91177308-0d34-0410-b5e6-96231b3b80d8