Add support for diffing against `sympy.Indexed` instances #3150

Job	Run time
{ "os": "ubuntu-20.04" }	1m 48s
{ "flag_warnings": "ON", "glibc_asserts": "ON", "os": "ubuntu-22.04" }	2m 58s
{ "os": "macos-13" }	3m 59s
{ "os": "macos-14" }	4m 21s
{ "os": "windows-latest" }	11m 0s
{ "os": "ubuntu-22.04", "sanitizer": "address-leak" }	2m 24s
{ "os": "ubuntu-22.04", "enable_usecases": "On", "update_references": "On" }	4m 3s
{ "flag_warnings": "ON", "os": "ubuntu-22.04", "sanitizer": "undefined" }	2m 9s
commit-references	5s
	32m 47s

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