fuzzing: Improve testcase isolation by draining the IPC staging queue #23511

Job	Run time
manifest-check	2m 52s
LP64-WIP	4m 10s
build-windows (mnfst, imx8 imx8x)	9m 43s
build-windows (mnfst, lnl)	8m 33s
build-windows (-d, mnfst, lnl)	9m 37s
build-linux (mnfst, lnl)	4m 37s
build-linux (mnfst, wcl imx95)	7m 31s
build-windows (mnfst, ptl)	9m 51s
build-linux (mnfst, tgl-h)	4m 24s
build-windows (mnfst, tgl-h)	9m 41s
build-windows (mnfst, mtl)	10m 32s
build-linux (-d, mnfst, lnl)	4m 45s
build-windows (mnfst, imx8m imx8ulp)	9m 26s
build-linux (mnfst, tgl)	4m 19s
build-windows (mnfst, tgl)	9m 30s
build-linux (mnfst, ptl)	5m 52s
build-linux (mnfst, mtl)	4m 57s
build-linux (mnfst, imx8 imx8x)	5m 3s
build-linux (mnfst, imx8m imx8ulp)	4m 54s
compare-linux-win	28s
	2h 10m 45s

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