clang-format: [JavaScript] Do requoting in a separate pass

The attempt to fix requoting behavior in r280487 after changes to
tooling::Replacements are incomplete. We essentially need to add to
replacements at the same position, one to insert a line break and one to
change the quoting and that's incompatible with the new
tooling::Replacement API, which does not allow for order-dependent
Replacements. To make the order clear, Replacements::merge() has to be
used, but that requires the merged Replacement to actually refer to the
changed text, which is hard to reproduce for the requoting.

This change fixes the behavior by moving the requoting to a completely
separate pass. The added benefit is that no weird ColumnWidth
calculations are necessary anymore and this should just work even if we
implement string literal splitting in the future.

llvm-svn: 280874