Disable pbxt for test cases not using pbxt (speeds up test suite)

extra/comp_err.c:
  Added cast to get rid of compiler warning
extra/libevent/kqueue.c:
  Added cast to get rid of compiler warning
mysql-test/lib/mtr_cases.pm:
  Use --skip-pbxt for test cases that doesn't need pbxt
  Collect default-storage-engine from suite.opt file (should actually be my.cnf file, but that wasn't easy to do)
mysql-test/suite/pbxt/t/suite.opt:
  Added marker for mysql-test-run.pl that this suite require pbxt
mysys/mf_keycache.c:
  Use LINT_INIT() to remove compiler warnings
mysys/my_gethostbyname.c:
  Remove compiler warnings
sql/handler.cc:
  Reset variable that may be used uninitialized
sql/item.h:
  Remove compiler warning
sql/mysqld.cc:
  Use LINT_INIT() to remove compiler warnings
sql/sql_class.h:
  Remove compiler warning
sql/sql_table.cc:
  Ensure variable is always set (to remove compiler warning)
sql/sql_view.cc:
  Use LINT_INIT() to remove compiler warnings
storage/maria/ma_loghandler.c:
  Use LINT_INIT() to remove compiler warnings
storage/myisammrg/ha_myisammrg.cc:
  Fixed wrong type to printf
storage/myisammrg/myrg_open.c:
  Use LINT_INIT() to remove compiler warnings
storage/xtradb/include/ut0lst.h:
  Trivial change of macro to remove compiler warning
strings/ctype-ucs2.c:
  Use LINT_INIT() to remove compiler warnings
strings/ctype-utf8.c:
  Use LINT_INIT() to remove compiler warnings
support-files/compiler_warnings.supp:
  Suppress some not relevant warnings
unittest/mysys/waiting_threads-t.c:
  Don't use ftruncate() as this gives warning about ignored return value