clang-format: [JS] Sort all JavaScript imports if any changed.

Summary:
User feedback is that they expect *all* imports to be sorted if any import was
affected by a change, not just imports up to the first non-affected line, as
clang-format currently does.

Reviewers: djasper

Subscribers: klimek, cfe-commits

Differential Revision: https://reviews.llvm.org/D23972

llvm-svn: 280485