test: remove unused test files

Closes #5169

(cherry picked from commit a661bef70d4ff2ba511c6e6ea71e95c6f50beb49)

.luacheckrc

@@ -33,12 +33,6 @@ exclude_files = {
     "test-run/**/*.lua",
     "test/app/*.test.lua",
     "test/box/*.test.lua",
-    -- Unused source file, to be dropped (gh-5169).
-    "test/box/lua/require_init.lua",
-    -- Unused source file, to be dropped (gh-5169).
-    "test/box/lua/require_mod.lua",
-    -- Unused source file, to be dropped (gh-5169).
-    "test/box/lua/test_init.lua",
     "test/engine/**/*.lua",
     "test/engine_long/**/*.lua",
     "test/luajit-tap/**/*.lua",

test/box/lua/require_init.lua

-#!/usr/bin/env tarantool
-box.load_cfg()
-mod = require("require_mod")
-package_path = package.path
-package_cpath = package.cpath

test/box/lua/require_mod.lua

-exports = {}
-
-function exports.test(a, b)
-  return a+b
-end
-
-return exports

test/box/lua/test_init.lua

-#!/usr/bin/env tarantool
-box.load_cfg()
--- testing start-up script
-floor = require("math").floor
-
---
--- Access to box.cfg from start-up script
---
-
-box_cfg = box.cfg()
-
-function print_config()
-	return box_cfg
-end
-
-
---
--- Test for bug #977898
--- Insert from detached fiber
---
-
-local function do_insert()
-    box.fiber.detach()
-    box.space[0]:insert{1, 2, 4, 8}
-end
-
-space = box.schema.create_space('tweedledum', { id = 0 })
-space:create_index('primary', { type = 'hash' })
-
-fiber = box.fiber.create(do_insert)
-box.fiber.resume(fiber)
-
---
--- Test insert from start-up script
---
-
-space:insert{2, 4, 8, 16}
-
---
--- A test case for https://github.com/tarantool/tarantool/issues/53
---
-
-assert (require ~= nil)
-box.fiber.sleep(0.0)
-assert (require ~= nil)