Pull request #1030: CAS-14758: Optimize image processing by caching tool handles in fill_summary_minor to avoid redundant open/close operations
Merge in CASA/casa6 from CAS-14758 to master
* commit 'a46b0fa46be4985558dfe705e9f2eccf577b4aed': CAS-14758: Handle missing residual images when constructing minor cycle summary CAS-14758: Optimize image processing by caching tool handles in fill_summary_minor to avoid redundant open/close operations