twsinst efficiency improvements

Ref: TS011706916

We've noted when upgrading from 9.4 to 9.5, and also when applying fixpacks to 9.5, that twsinst is performing "copy" operations on all the files in the stdlist directory instead of "move" operations. This has led to two issues during our upgrade/patch cycles:

First, by copying, additional storage is required. The process twsinst appears to follow is to:

1. Rename (or "move") the stdlist directory to a temporary name.

2. Recreate the stdlist directory.

3. Copy the contents from the original (now temporary) directory structure back to the newly created stdlist directory.

4. Remove the temporary directory.

This leads to a requirement for double the size of the stdlist directory during the upgrade/patch activity. Unfortunately, twsinst does not perform a sufficiently robust check to verify it has enough storage for this, and has caused us to lose log files as a result.

The second side issue is that the "copy" operations take significantly more time than a "move" would. For systems running a small number of batches this is an insignificant improvement, but we have systems that run 20k batches per day and we're keeping 45 days of log history on the server, which creates a significant delay in the patching activity.

As all of this is being done as "root", as required by twsinst operations, there is no benefit to having this being done as a copy. It should be changed to operate as a "move" instead.