adb: implement std::make_unique, start using it.

Add an implementation of std::make_unique for Windows, where we're
currently stuck with C++11, and switch some uses of new over to it.

Bug: http://b/74616284
Test: treehugger
Change-Id: I99b85f07754adda7c525243480c3e0bce9a25ce7
(cherry picked from commit 31b5be69)