Ruby

test_object_id.rb: use better randomness

When the test is repeated 20 or more times in the same process
it's not that unlikely for rand(100_000) to return the same thing
twice, causing TestObjectIdTooComplexClass to fail.

  1) Failure:
TestObjectIdTooComplexClass#test_dup_with_id_and_ivar [/tmp/ruby/src/trunk-repeat20-asserts/test/ruby/test_object_id.rb:172]:
Expected #<struct RubyVM::Shape
 id=6783,
 parent_id=6774,
 edge_name=:@___26417,
 next_field_index=2,
 heap_index=0,
 type=1,
 capacity=7> to be too_complex?.