Please not the memory issue which is mentioned here is not for the application server, it is applicable for the box from which the upgrade scripts are running.
In the resolution of the support article it is mentioned to keep minimum heap size to 512 mb, however generally we keep the minimum heap size to 2048mb and maximum 4096mb, so if you have enough memory in the box you can increase it.
The windows server 2012 has a power shell command line which is having elevated security. The upgrade wizard for the failed run’s were through the power shell command line. The power shell was denying the creation of the virtual machine.
Run the upgrade wizard through the normal command line. The base values(jvm allocation) mentioned in the PEGA artifacts is sufficent to complete the upgrade.