instr_bs.cpp: Improve coverage #4632

Job	Run time
Build Erlang/OTP (64-bit)	8m 33s
Event File	2s
Create SBOM	0s
Build Erlang/OTP (iOS)	3m 35s
Build Erlang/OTP (macOS)	2m 45s
Build Erlang/OTP (32-bit)	4m 52s
Build Erlang/OTP (Windows)	17m 58s
Build Erlang/OTP (cross-compile)	10m 2s
Build Erlang/OTP (Types and Flavors)	11m 9s
Build Erlang/OTP (clang)	5m 17s
Build and check documentation	4m 46s
Build Erlang/OTP (FreeBSD)	3m 28s
Run static analysis	6m 7s
Test Erlang/OTP (emulator)	49m 37s
Test Erlang/OTP (debug)	4m 26s
Release Erlang/OTP	0s
Test Erlang/OTP (system)	7m 25s
	2h 20m 2s

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