Here is a formula based solution:
I have assumed your original data is in columns A and B.
Your re-arranged data is created starting at D2.
Two dynamic named ranges that cover the source data must be created:
Column-D derives the unique items from the source data SKUs in column-A
In d2:
In E2 commit as an array formula using CTRL-SHIFT-ENTER:
Copy E2 rightwards for at least the maximum number of URLs per SKU that you expect to have.
Copy all the column-D onwards formulas downwards for at least as many unique SKUs you have.
The attached workbook implements the above.
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