[CMAKE] Add DEBUG and DEBUG_LOCKORDER definitions to the Debug config

Summary:
This add definitions for DEBUG and DEBUG_LOCKORDER when the Debug
build type is used.
This allow the use of cmake -GNinja -DCMAKE_BUILD_TYPE=Debug as an
equivalent to configure --enable-debug.

Test Plan:

mkdir buildcmake && cd buildcmake
cmake -GNinja .. -DCMAKE_BUILD_TYPE=Debug
ninja -v

Check that the -DDEBUG -DDEBUG_LOCKORDER flags are added to the
CXX compile lines.

Reviewers: #bitcoin_abc, deadalnix, jasonbcox

Reviewed By: #bitcoin_abc, jasonbcox

Subscribers: teamcity, schancel

Differential Revision: https://reviews.bitcoinabc.org/D2656