[scudo] Use cast on calls to __builtin_umul_overflow/__builtin_umull_overflow am: 82ea5b5cf6

Original change: https://android-review.googlesource.com/c/platform/external/scudo/+/2063220

Change-Id: I3f837921b1dfccc13c8e201c7de84cac967b5f52
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>