Empty ranges do not overlap with any range.

Regarding benchmarks, PR#8242 is significantly faster in some cases,
but one of these two cases is a wrong result.

|                           |ActiveSupport| PR#8242|built-ruby|
|:--------------------------|------------:|-------:|---------:|
|(2..3).overlap?(1..1)      |       7.761M| 15.053M|   32.368M|
|                           |            -|   1.94x|     4.17x|
|(2..3).overlap?(2..4)      |      25.720M| 55.070M|   21.981M|
|                           |        1.17x|   2.51x|         -|
|(2..3).overlap?(4..5)      |       7.616M| 15.048M|   21.730M|
|                           |            -|   1.98x|     2.85x|
|(2..3).overlap?(2..1)      |      25.585M| 56.545M|   32.786M|
|                           |            -|   2.21x|     1.28x|
|(2..3).overlap?(0..1)      |       7.554M| 14.755M|   32.545M|
|                           |            -|   1.95x|     4.31x|
|(2..3).overlap?(...1)      |       6.681M|  5.843M|   32.255M|
|                           |        1.14x|       -|     5.52x|
|(2...3).overlap?(..2)      |       6.676M|  5.817M|   21.572M|
|                           |        1.15x|       -|     3.71x|
|(2...3).overlap?(3...)     |       7.392M| 14.755M|   31.805M|
|                           |            -|   2.00x|     4.30x|
|(2..3).overlap?('a'..'d')  |       3.675M|  3.482M|   17.009M|
|                           |        1.06x|       -|     4.89x|