Automated g4 rollback of changelist 604607692.

*** Reason for rollback ***

breakage resulting in "inertia must have positive eigenvalues" when parsing URDF's

*** Original change description ***

Move fullinertia from mjCAlternative to mjCBody.

***

PiperOrigin-RevId: 604677400
Change-Id: Iab8263b5b0aee310bd75404e314f3b707ce3300e

src/user/user_flexcomp.cc

@@ -117,7 +117,7 @@ bool mjCFlexcomp::Make(mjCModel* model, mjCBody* body, char* error, int error_sz
   }
 
   // compute orientation
-  const char* alterr = alt.Set(quat, model->degree, model->euler);
+  const char* alterr = alt.Set(quat, NULL, model->degree, model->euler);
   if (alterr) {
     return comperr(error, alterr, error_sz);
   }