smex: harden ELF parsing against malformed input #23565

Job	Run time
LP64-WIP	3m 53s
manifest-check	2m 42s
build-windows (mnfst, lnl)	9m 16s
build-linux (mnfst, tgl)	4m 12s
build-linux (mnfst, ptl)	5m 50s
build-windows (mnfst, tgl)	9m 0s
build-linux (mnfst, imx8 imx8x)	4m 51s
build-windows (mnfst, ptl)	10m 17s
build-windows (mnfst, imx8m imx8ulp)	10m 24s
build-windows (mnfst, tgl-h)	8m 5s
build-linux (mnfst, lnl)	4m 23s
build-windows (mnfst, imx8 imx8x)	10m 0s
build-linux (-d, mnfst, lnl)	4m 48s
build-linux (mnfst, wcl imx95)	7m 20s
build-windows (-d, mnfst, lnl)	8m 34s
build-windows (mnfst, mtl)	8m 31s
build-linux (mnfst, tgl-h)	4m 14s
build-linux (mnfst, imx8m imx8ulp)	5m 9s
build-linux (mnfst, mtl)	5m 1s
compare-linux-win	28s
	2h 6m 58s

Provide feedback