Add regtests to distinguish between ptr value and deref bounds #15766

Job	Run time
regression (ubuntu-latest, ocaml-variants.4.14.2+options,ocaml-option-flambda)	7m 32s
regression (macos-latest, ocaml-variants.4.14.2+options,ocaml-option-flambda)	13m 52s
extraction	0s
	21m 24s

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