clang-format: [JS] do not break after declare namespace.
clang-format: [JS] do not break after declare namespace.

Summary:
See TypeScript grammar for tokens following 'declare':
https://github.com/Microsoft/TypeScript/blob/master/doc/spec.md#A.10

Additional minor change:
clang-format: [JS] Prevent ASI before const.

Reviewers: djasper

Subscribers: cfe-commits, klimek

Differential Revision: https://reviews.llvm.org/D26274

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@286468 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang