test/cases/0120-misc: unique_object test fails on Lua 5.2 and sometimes on Lua 5.3

[E-Fir]

test/cases/0120-misc.lua
unique_object test fails on Lua 5.2

Suite test	unique_object
test/cases/0120-misc.lua:60: ensure_equals failed: all objects are unique: actual `1', expected `100'
stack traceback:
	[C]: in function 'error'
	lua-nucleo/ensure.lua:62: in function 'ensure_equals'
	test/cases/0120-misc.lua:60: in function 'fn'
	lua-nucleo/suite.lua:173: in function <lua-nucleo/suite.lua:173>
	[C]: in function 'xpcall'
	lua-nucleo/suite.lua:173: in function 'run'
	lua-nucleo/suite.lua:616: in function <lua-nucleo/suite.lua:612>
	[C]: in function 'xpcall'
	lua-nucleo/suite.lua:611: in function 'run_test'
	lua-nucleo/suite.lua:662: in function 'run_tests'
	test/test.lua:181: in main chunk
	[C]: in ?