clang-format: [JS] Fix template string ASI.

Summary:
Previously, automatic semicolon insertion would add an unwrapped line
when a template string contained a line break.

    var x = `foo${
        bar}`;

Would be formatted with `bar...` on a separate line and no indent.

Reviewers: djasper

Subscribers: cfe-commits, klimek

Differential Revision: https://reviews.llvm.org/D25675

llvm-svn: 284807