Switch to collision boolean only GJK for contacts instead of using S3D.

PiperOrigin-RevId: 682329224
Change-Id: I3db141b0482610a0a88854f47a46b0b7b694b361

src/engine/engine_collision_gjk.h

@@ -48,6 +48,7 @@ struct _mjCCDStatus {
   int epa_iterations;         // number of iterations that EPA ran (negative if EPA did not run)
   mjtNum simplex1[12];        // the simplex that GJK returned for obj1
   mjtNum simplex2[12];        // the simplex that GJK returned for obj2
+  mjtNum simplex[12];         // the simplex that GJK returned for the Minkowski difference
   int nsimplex;               // size of simplex 1 & 2
 };
 typedef struct _mjCCDStatus mjCCDStatus;