- SAFEMALLOC should be defined for each project in debug Windows builds.
SAFEMALLOC was not defined for the innodb project. Debug asserts caused 
due to mixed SAFEMALLOC defines.


innobase/CMakeLists.txt:
  Bug#25765 too many dbg heap assertions on windows
  - Make sure that *_DEBUG defaults are not overwritten.
  - Define SAFEMALLOC and SAFE_MUTEX for debug innodb builds.