[wp] fix chunk ordering bug

src/plugins/wp/MemBytes.ml

src/plugins/wp/MemRegion.ml

src/plugins/wp/MemTyped.ml

src/plugins/wp/MemVal.ml

src/plugins/wp/MemVar.ml

src/plugins/wp/MemZeroAlias.ml

src/plugins/wp/Mstate.ml

src/plugins/wp/Sigma.ml

src/plugins/wp/Sigma.mli

.../tests/wp/oracle_qualif/stmtcompiler_test_rela.res.oracle

src/plugins/wp/tests/wp/stmtcompiler_test_rela.ml

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

src/plugins/wp/tests/wp_usage/oracle/caveat2.res.oracle