Reduce shrink() method calls to size() by leveraging targetLabelSize

The shrink() method previously called the size() function multiple
times, impacting performance. This commit optimizes the logic by only
checking if the targetLabelSize has changed, which effectively
determines whether the program size needs shrinking.

Bug: 293811969
Test: TH
Change-Id: Ia750820767e2b8df249dcdb536ce4d7241ac2d7d