Remove MuJoCo stack calls in nativeccd.

1. There is now thread local static memory for use with a conservative max number of iterations needed for contact.
2. For possible needs of high precision contact recovery with large iteration numbers (i.e. ellipsoid-ellipsoid collisions), there are callbacks to allocate memory when needed.

PiperOrigin-RevId: 739187134
Change-Id: I3d210f75218922d969c78465da3fe50da4fe3080

test/engine/engine_collision_gjk_test.cc

@@ -17,6 +17,7 @@
 #include "src/engine/engine_collision_gjk.h"
 
 #include <array>
+#include <cstddef>
 #include <vector>
 
 #include <ccd/ccd.h>
@@ -61,6 +62,14 @@ constexpr char kEllipoid[] = R"(
   </keyframe>
 </mujoco>)";
 
+void* CCDAllocate(void* data, std::size_t nbytes) {
+  return new std::byte[nbytes];
+}
+
+void CCDFree(void* data, void* buffer) {
+  delete [] (std::byte*)buffer;
+}
+
 mjtNum GeomDist(mjModel* m, mjData* d, int g1, int g2, mjtNum x1[3],
                 mjtNum x2[3], mjtNum cutoff = mjMAXVAL) {
   mjCCDConfig config;
@@ -127,6 +136,9 @@ int Penetration(mjtNum& depth, std::vector<mjtNum>& dir,
   config.max_contacts = max_contacts;
   config.dist_cutoff = 0;  // no geom distances needed
   config.max_contacts = max_contacts;
+  config.context = nullptr;
+  config.alloc = CCDAllocate;
+  config.free = CCDFree;
 
   mjtNum dist = mjc_ccd(&config, &status, &obj1, &obj2);
   if (dist < 0) {