Fix uninitialized buffers in QTB (#5163)

adaptFrictionPart1 is executed first, it reads randomForce and
segmentVelocity buffers before other kernels write them so they can
contain garbage after allocation (cuMemAlloc/hipMalloc/clCreateBuffer
do not clear allocated memory).

platforms/common/src/CommonIntegrateQTBStepKernel.cpp

@@ -51,7 +51,9 @@ void CommonIntegrateQTBStepKernel::initialize(const System& system, const QTBInt
     noise.upload(noiseVec);
     int elementSize = (cc.getUseMixedPrecision() || cc.getUseDoublePrecision() ? sizeof(double) : sizeof(float));
     randomForce.initialize(cc, 3*segmentLength*numParticles, elementSize, "randomForce");
+    cc.clearBuffer(randomForce);
     segmentVelocity.initialize(cc, 3*segmentLength*numParticles, elementSize, "segmentVelocity");
+    cc.clearBuffer(segmentVelocity);
     oldDelta.initialize(cc, cc.getPaddedNumAtoms(), 4*elementSize, "oldDelta");
     thetad.initialize(cc, numFreq, elementSize, "thetad");
     workspace.initialize(cc, 18*segmentLength*cc.getNumThreadBlocks(), elementSize, "workspace");