occasional segfault surface smoother from matlab

[ahbarnett]

This is not reproducible. R2022a.4 on ubuntu 22.04 linux. It happened once. FYI:

o.nrefine = 1;
Sarr = multiscale_mesher('../geometries/meshes/cuboid_a1_b2_c1p3.tri',4,o);
 successfully read input mesh
 -----------------------------

 Starting surface smoother now

 -----------------------------------
 Refinement:           0
 -----------------------------------
 iteration,  #targets,   err
         1     4800       0.10E+01
         2     1294       0.15E-01
         3      418       0.26E-03
         4       76       0.32E-07
         5        0       0.96E-10

 -----------------------------------
 Refinement:           1
 -----------------------------------
 iteration,  #targets,   err
         1    19200       0.10E+01
         2    10425       0.36E-01
         3     5838       0.24E-01
         4     1239       0.22E+00
         5      239       0.10E+01
         6        4       0.10E+01
free(): invalid next size (normal)
free(): invalid next size (normal)
free(): invalid next size (normal)
free(): invalid next size (normal)
free(): invalid next size (normal)
free(): invalid next size (normal)
free(): invalid next size (normal)
Aborted (core dumped)