Auto merge of #15469 - stshine:no-integer-overflow, r=emilio

layout: Fix integer overflow when computing size of replace elements

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When calculating size of replaced element that has intrinsic aspect ratio, we need to multiply the ratio if one of the dimensions has definite size. And we can not precompute the ratio and store it as a float, because doing so may result one pixel difference in calculation for certain images, thus make some tests fail. So it may overflow when the dimension lengths are large, and this pull request convert them to `i64` before multiplication.

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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #15249 (github issue number if applicable).

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