Fix RNG memory leak on various error conditions

This memory leak shows up in the flaky blendfile_versioning test, and
this may help fix it.

source/blender/blenkernel/intern/cloth.cc

@@ -1565,6 +1565,7 @@ static bool cloth_build_springs(ClothModifierData *clmd, Mesh *mesh)
           if (tmp_mesh) {
             BKE_id_free(nullptr, &tmp_mesh->id);
           }
+          BLI_rng_free(rng);
           return false;
         }
       }

source/blender/blenkernel/intern/particle_system.cc

@@ -4353,6 +4353,7 @@ static void particles_fluid_step(ParticleSimulationData *sim,
           BLI_snprintf(debugStrBuffer,
                        sizeof(debugStrBuffer),
                        "particles_fluid_step::error - unknown particle system type\n");
+          BLI_rng_free(sim->rng);
           return;
         }
 #  if 0

source/blender/blenlib/tests/BLI_delaunay_2d_test.cc

@@ -2086,6 +2086,7 @@ void rand_delaunay_test(int test_kind,
         }
         default:
           std::cout << "unknown delaunay test type\n";
+          BLI_rng_free(rng);
           return;
       }
       if (otype != CDT_FULL) {