scripts: reset LLEXT VMA accumulators before each west build #23198

Job	Run time
build-windows (mnfst, tgl)	8m 22s
build-windows (mnfst, lnl)	9m 47s
build-linux (mnfst, imx8 imx8x)	5m 56s
build-windows (mnfst, imx8m imx8ulp)	11m 24s
manifest-check	3m 38s
build-linux (mnfst, imx8m imx8ulp)	5m 32s
build-windows (mnfst, tgl-h)	8m 12s
build-windows (mnfst, imx8 imx8x)	11m 9s
build-linux (mnfst, mtl)	5m 47s
build-linux (mnfst, lnl)	4m 29s
build-windows (mnfst, mtl)	10m 10s
build-linux (mnfst, ptl)	5m 51s
build-linux (mnfst, tgl-h)	4m 14s
build-windows (mnfst, ptl)	11m 42s
build-linux (-d, mnfst, lnl)	5m 6s
build-linux (mnfst, wcl imx95)	7m 36s
LP64-WIP	3m 57s
build-linux (mnfst, tgl)	4m 14s
build-windows (-d, mnfst, lnl)	12m 38s
compare-linux-win	25s
	2h 20m 9s

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