kallsyms: fix fd leak in AssignAddresses and AssignModules #1549

Job	Run time
Build and Lint	2m 12s
Build Documentation	24s
Run tests on arm64	38s
Run tests on previous stable Go	2m 3s
Run tests (mainline)	2m 42s
Run tests (stable)	1m 9s
Run tests (6.6)	1m 16s
Run tests (6.1)	1m 8s
Run tests (5.15)	1m 14s
Run tests (5.10)	1m 12s
Run tests (5.4)	1m 15s
Run tests (4.19)	1m 18s
Run tests (4.14)	1m 20s
Run tests (4.9)	1m 13s
	19m 4s

Provide feedback