CudaApplyConstraintsKernel::apply() did not set the context as current,...

CudaApplyConstraintsKernel::apply() did not set the context as current, leading to errors when using multiple contexts

platforms/cuda/src/CudaKernels.cpp

@@ -383,6 +383,7 @@ void CudaApplyConstraintsKernel::initialize(const System& system) {
 }
 
 void CudaApplyConstraintsKernel::apply(ContextImpl& context, double tol) {
+    cu.setAsCurrent();
     if (!hasInitializedKernel) {
         hasInitializedKernel = true;
         map<string, string> defines;