Remove std::unique_ptr dependency on bssl_shim's scoped types.

This is in preparation for using RAII in the unit tests. Those tests are built
in Chromium as well, but Chromium does not have C++11 library support across
all its toolchains. Compiler support is available, so add a partial
reimplementation of std::unique_ptr and std::move under crypto/test/. The
scopers for the crypto/ library are also moved there while the ones for ssl/
stay in ssl/test/.

Change-Id: I38f769acbc16a870db34649928575c7314b6e9f6
Reviewed-on: https://boringssl-review.googlesource.com/4120
Reviewed-by: Adam Langley <agl@google.com>
7 files changed