Attempt to fix boringssl tests

Commit abe256e7

 changed the config target
element from 'cxx' to 'CXX'; catch up accordingly.
Also use a space to offset the template boundary, per convention.

[extended tests]

Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5577)