schedule: zephyr_ll_user: improve heap init and make it usable from user-space #23230

Job	Run time
build-windows (mnfst, imx8m imx8ulp)	10m 26s
build-linux (mnfst, mtl)	4m 46s
build-linux (mnfst, ptl)	6m 7s
build-windows (mnfst, imx8 imx8x)	11m 19s
build-windows (mnfst, mtl)	10m 20s
build-linux (mnfst, lnl)	4m 39s
manifest-check	3m 28s
build-linux (mnfst, tgl)	4m 15s
build-windows (-d, mnfst, lnl)	11m 45s
build-windows (mnfst, lnl)	9m 12s
build-linux (-d, mnfst, lnl)	4m 33s
LP64-WIP	3m 50s
build-linux (mnfst, wcl imx95)	7m 34s
build-linux (mnfst, imx8 imx8x)	5m 49s
build-linux (mnfst, tgl-h)	4m 12s
build-windows (mnfst, tgl-h)	9m 12s
build-linux (mnfst, imx8m imx8ulp)	4m 52s
build-windows (mnfst, tgl)	6m 54s
build-windows (mnfst, ptl)	11m 20s
compare-linux-win	29s
	2h 15m 2s

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