d/patches: Make TrueType date calculations UTC-based (Closes #1128901)

Gioele Barabuccirequested to merge
gioele/bitsnpicas:patch-repro-timestamps-ttf-2 into master

Follow-up to !1 (merged). This fixes the unreproducibility of fonts-topaz-unicode when compiling with "extreme" timezones like GMT+12.

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