[wp] fix start-of array across all models

src/plugins/wp/CodeSemantics.ml

src/plugins/wp/Cvalues.ml

src/plugins/wp/Cvalues.mli

src/plugins/wp/LogicSemantics.ml

src/plugins/wp/MemTyped.ml

src/plugins/wp/RefUsage.ml

src/plugins/wp/Sigs.ml

src/plugins/wp/tests/wp_acsl/oracle/logic.res.oracle

src/plugins/wp/tests/wp_acsl/oracle/pointer.res.oracle

...gic.0.session/cache/3b92daa0c60a8fd3936ce9728c00cb1b.json

...gic.0.session/cache/73c06b555235a7d0c550272daddaaf5c.json

...gic.0.session/cache/850478f3d426778af16ee9be9a21ecb8.json

src/plugins/wp/tests/wp_acsl/oracle_qualif/logic.res.oracle

...ugins/wp/tests/wp_acsl/oracle_qualif/pointer.0.res.oracle

...ugins/wp/tests/wp_acsl/oracle_qualif/pointer.1.res.oracle

src/plugins/wp/tests/wp_bts/oracle/issue_715_a.res.oracle

...s/wp/tests/wp_bts/oracle_qualif/issue_715_a.0.report.json

...gins/wp/tests/wp_bts/oracle_qualif/issue_715_a.res.oracle

src/plugins/wp/tests/wp_hoare/oracle/logicarr.res.oracle

...arr.0.session/cache/1fed73d94cd3ea7e79e26165deb00a73.json