gh-1171: long-run test suite, rewrite in engine-independent way

src/box/phia_engine.cc

test/engine_long/box.lua

test/engine_long/delete_insert.result

test/engine_long/delete_insert.test.lua

test/engine_long/delete_replace_update.result

test/engine_long/delete_replace_update.test.lua

test/engine_long/engine.cfg

test/engine_long/suite.ini

test/engine_long/suite.lua

test/long_run/lua/finalizers.lua

test/long_run/memtx_delete_insert.test.lua

test/long_run/phia_delete_insert.result

test/long_run/phia_delete_insert.test.lua

test/long_run/phia_delete_replace_update.result

test/long_run/phia_delete_replace_update.test.lua

test/long_run/suite.ini