don't run tests depending on the generic lock manager which will be
removed; don't run page cache unit tests by default (too intensive).


storage/maria/unittest/Makefile.am:
  don't run tests depending on the generic lock manager (it will 
  be removed in the end), one of them crashes.
unittest/mysys/Makefile.am:
  page cache tests put a too high load, causes problems on shared machines;
  so we still build them but give them a suffix so that they are
  not run by the default "test-unit" Makefile target.