Resource merge in release path ignores address contiguity - creates false spans across unmanaged gaps

Summary

int_rman_release_resource (subr_rman.c:563-583): merge checks only RF_ALLOCATED==0 on neighbors s/t, NEVER address contiguity. :568 s->r_end=t->r_end (3-way) :576 s->r_end=r->r_end (prev) :582 t->r_start=r->r_start (next) all blindly extend neighbor bounds absorbing r across any gap. ACPI rman (acpi.c:1099 one rman_manage_region per _CRS) has non-contiguous regions e.g. [0,0xFF]+[0x200,0x2FF] gap [0x100,0x1FF]. Allocate+release in one region merges across gap -> subsequent rman_reserve_resource (:254 check passes) allocates within gap -> driver gets unmanaged MMIO/IOPORT. Code bug certain; cross-device MMIO impact speculative (driver must request gap range).