Fix linker warning for C++ tests #2512

Job	Run time
Analyze (cpp, ubuntu-latest, CC=gcc CXX=g++, no, no)	3m 54s
Analyze (cpp, ubuntu-latest, CC=gcc CXX=g++, no, libusb-1.0)	4m 15s
Analyze (cpp, ubuntu-latest, CC=gcc CXX=g++, no, libusb-0.1)	4m 25s
Analyze (cpp, ubuntu-latest, CC=gcc CXX=g++, nss, no)	4m 35s
Analyze (cpp, ubuntu-latest, CC=gcc CXX=g++, nss, libusb-1.0)	4m 40s
Analyze (cpp, ubuntu-latest, CC=gcc CXX=g++, nss, libusb-0.1)	4m 33s
Analyze (cpp, ubuntu-latest, CC=gcc CXX=g++, openssl, no)	4m 56s
Analyze (cpp, ubuntu-latest, CC=gcc CXX=g++, openssl, libusb-1.0)	4m 30s
Analyze (cpp, ubuntu-latest, CC=gcc CXX=g++, openssl, libusb-0.1)	4m 31s
Analyze (cpp, ubuntu-latest, CC=clang CXX=clang++, no, no)	4m 6s
Analyze (cpp, ubuntu-latest, CC=clang CXX=clang++, no, libusb-1.0)	4m 36s
Analyze (cpp, ubuntu-latest, CC=clang CXX=clang++, no, libusb-0.1)	4m 41s
Analyze (cpp, ubuntu-latest, CC=clang CXX=clang++, nss, no)	4m 14s
Analyze (cpp, ubuntu-latest, CC=clang CXX=clang++, nss, libusb-1.0)	4m 55s
Analyze (cpp, ubuntu-latest, CC=clang CXX=clang++, nss, libusb-0.1)	4m 25s
Analyze (cpp, ubuntu-latest, CC=clang CXX=clang++, openssl, no)	4m 14s
Analyze (cpp, ubuntu-latest, CC=clang CXX=clang++, openssl, libusb-1.0)	4m 28s
Analyze (cpp, ubuntu-latest, CC=clang CXX=clang++, openssl, libusb-0.1)	4m 40s
Analyze (python, ubuntu-latest, PYTHON=python3, no, no)	54s
	1h 21m 32s

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