fix: retain clock information after isolate_subsystem

[AayushSabharwal]

Checklist

• Appropriate tests were added
• Any code changes were done in a way that does not break public API
• All documentation related to code changes were updated
• The new code follows the
  contributor guidelines, in particular the SciML Style Guide and
  COLPRAC.
• Any new documentation only uses public API

Additional context

Add any other context about the problem here.

[github-actions]

Benchmark Results (Julia vlts)

Time benchmarks

	master	313cc25...	master / 313cc25...
ODEProblem	5.64 ± 0.14 ms	5.69 ± 0.15 ms	0.99 ± 0.036
init	0.0729 ± 0.027 ms	0.0729 ± 0.027 ms	1 ± 0.53
large_parameter_init/ODEProblem	23.3 ± 4.3 ms	23.4 ± 4 ms	0.999 ± 0.25
large_parameter_init/init	0.108 ± 0.042 ms	0.0932 ± 0.034 ms	1.16 ± 0.62
mtkcompile	9.49 ± 0.3 ms	9.67 ± 0.27 ms	0.981 ± 0.042
sparse_analytical_jacobian/ODEProblem	26.5 ± 1.5 ms	26.8 ± 1.6 ms	0.989 ± 0.082
sparse_analytical_jacobian/f_iip	0.07 ± 0 μs	0.07 ± 0 μs	1 ± 0
sparse_analytical_jacobian/f_oop	0.383 ± 0.011 ms	0.381 ± 0.012 ms	1 ± 0.043
time_to_load	5.82 ± 0.022 s	5.81 ± 0.0029 s	1 ± 0.0038

Memory benchmarks

	master	313cc25...	master / 313cc25...
ODEProblem	0.0402 M allocs: 2.21 MB	0.0402 M allocs: 2.23 MB	0.993
init	0.417 k allocs: 0.0698 MB	0.417 k allocs: 0.0698 MB	1
large_parameter_init/ODEProblem	0.325 M allocs: 11.4 MB	0.325 M allocs: 11.4 MB	1
large_parameter_init/init	0.605 k allocs: 0.172 MB	0.605 k allocs: 0.172 MB	1
mtkcompile	0.0621 M allocs: 3.41 MB	0.0621 M allocs: 3.41 MB	1
sparse_analytical_jacobian/ODEProblem	0.195 M allocs: 8.06 MB	0.195 M allocs: 8.06 MB	1
sparse_analytical_jacobian/f_iip	0 allocs: 0 B	0 allocs: 0 B
sparse_analytical_jacobian/f_oop	0.634 k allocs: 19.6 kB	0.634 k allocs: 19.6 kB	1
time_to_load	0.153 k allocs: 14.5 kB	0.153 k allocs: 14.5 kB	1

[github-actions]

Benchmark Results (Julia v1)

Time benchmarks

	master	313cc25...	master / 313cc25...
ODEProblem	5.11 ± 0.28 ms	4.91 ± 0.2 ms	1.04 ± 0.07
init	0.0538 ± 0.018 ms	0.0548 ± 0.018 ms	0.983 ± 0.46
large_parameter_init/ODEProblem	25.3 ± 4.7 ms	24.9 ± 5 ms	1.02 ± 0.28
large_parameter_init/init	0.075 ± 0.036 ms	0.0736 ± 0.037 ms	1.02 ± 0.71
mtkcompile	8.55 ± 0.67 ms	7.92 ± 0.32 ms	1.08 ± 0.095
sparse_analytical_jacobian/ODEProblem	23.4 ± 3.1 ms	22.8 ± 2.7 ms	1.03 ± 0.18
sparse_analytical_jacobian/f_iip	0.09 ± 0.01 μs	0.081 ± 0.01 μs	1.11 ± 0.18
sparse_analytical_jacobian/f_oop	0.115 ± 0.012 ms	0.115 ± 0.012 ms	1 ± 0.15
time_to_load	5.65 ± 0.029 s	5.66 ± 0.029 s	0.998 ± 0.0072

Memory benchmarks

	master	313cc25...	master / 313cc25...
ODEProblem	0.0396 M allocs: 1.79 MB	0.0396 M allocs: 1.79 MB	1
init	0.416 k allocs: 0.0518 MB	0.416 k allocs: 0.0518 MB	1
large_parameter_init/ODEProblem	0.353 M allocs: 12.8 MB	0.353 M allocs: 12.8 MB	1
large_parameter_init/init	0.799 k allocs: 0.152 MB	0.799 k allocs: 0.152 MB	1
mtkcompile	0.0601 M allocs: 2.68 MB	0.0601 M allocs: 2.68 MB	1
sparse_analytical_jacobian/ODEProblem	0.188 M allocs: 7 MB	0.188 M allocs: 7 MB	1
sparse_analytical_jacobian/f_iip	0 allocs: 0 B	0 allocs: 0 B
sparse_analytical_jacobian/f_oop	0.848 k allocs: 27 kB	0.848 k allocs: 27 kB	1
time_to_load	0.145 k allocs: 11 kB	0.145 k allocs: 11 kB	1