location prop set: skip update if new value == old,

[ikreymer]

sometimes results in spurious refresh, and can err on side of skipping (ex: https://neural.love/ai-art-generator/1ede9fe2-9a61-6fe8-b093-25bfc69c7b3b/biopunk-factory) Part of fix for webrecorder/archiveweb.page#156