Assert input stream validity when reading XML.
Assert input stream validity when reading XML.

As was discovered in 2bc6f8c810, every other ParameterHandler method
that takes an input stream argument and reads from it throws an
exception if the input stream is not in a valid state.

sairajat/dealii,naliboff/dealii,pesser/dealii,angelrca/dealii,JaeryunYim/dealii,jperryhouts/dealii,danshapero/dealii,EGP-CIG-REU/dealii,angelrca/dealii,EGP-CIG-REU/dealii,shakirbsm/dealii,kalj/dealii,sairajat/dealii,sairajat/dealii,danshapero/dealii,shakirbsm/dealii,kalj/dealii,naliboff/dealii,angelrca/dealii,kalj/dealii,kalj/dealii,JaeryunYim/dealii,naliboff/dealii,kalj/dealii,jperryhouts/dealii,pesser/dealii,jperryhouts/dealii,JaeryunYim/dealii,EGP-CIG-REU/dealii,danshapero/dealii,naliboff/dealii,sairajat/dealii,spco/dealii,spco/dealii,naliboff/dealii,angelrca/dealii,spco/dealii,danshapero/dealii,naliboff/dealii,JaeryunYim/dealii,kalj/dealii,danshapero/dealii,EGP-CIG-REU/dealii,jperryhouts/dealii,JaeryunYim/dealii,pesser/dealii,spco/dealii,EGP-CIG-REU/dealii,naliboff/dealii,angelrca/dealii,jperryhouts/dealii,kalj/dealii,pesser/dealii,shakirbsm/dealii,angelrca/dealii,pesser/dealii,danshapero/dealii,pesser/dealii,sairajat/dealii,shakirbsm/dealii,JaeryunYim/dealii,sairajat/dealii,shakirbsm/dealii,spco/dealii,angelrca/dealii,jperryhouts/dealii,EGP-CIG-REU/dealii,spco/dealii,shakirbsm/dealii,sairajat/dealii,JaeryunYim/dealii,pesser/dealii,shakirbsm/dealii,EGP-CIG-REU/dealii,jperryhouts/dealii,danshapero/dealii,spco/dealii