Fix linker warning for C++ tests #2629

Job	Run time
Analyze (cpp, ubuntu-latest, CC=gcc CXX=g++, no, no)	4m 36s
Analyze (cpp, ubuntu-latest, CC=gcc CXX=g++, no, libusb-1.0)	4m 58s
Analyze (cpp, ubuntu-latest, CC=gcc CXX=g++, no, libusb-0.1)	4m 38s
Analyze (cpp, ubuntu-latest, CC=gcc CXX=g++, nss, no)	4m 40s
Analyze (cpp, ubuntu-latest, CC=gcc CXX=g++, nss, libusb-1.0)	6m 25s
Analyze (cpp, ubuntu-latest, CC=gcc CXX=g++, nss, libusb-0.1)	5m 7s
Analyze (cpp, ubuntu-latest, CC=gcc CXX=g++, openssl, no)	6m 9s
Analyze (cpp, ubuntu-latest, CC=gcc CXX=g++, openssl, libusb-1.0)	6m 4s
Analyze (cpp, ubuntu-latest, CC=gcc CXX=g++, openssl, libusb-0.1)	6m 10s
Analyze (cpp, ubuntu-latest, CC=clang CXX=clang++, no, no)	5m 20s
Analyze (cpp, ubuntu-latest, CC=clang CXX=clang++, no, libusb-1.0)	4m 55s
Analyze (cpp, ubuntu-latest, CC=clang CXX=clang++, no, libusb-0.1)	4m 51s
Analyze (cpp, ubuntu-latest, CC=clang CXX=clang++, nss, no)	4m 53s
Analyze (cpp, ubuntu-latest, CC=clang CXX=clang++, nss, libusb-1.0)	5m 20s
Analyze (cpp, ubuntu-latest, CC=clang CXX=clang++, nss, libusb-0.1)	4m 55s
Analyze (cpp, ubuntu-latest, CC=clang CXX=clang++, openssl, no)	4m 48s
Analyze (cpp, ubuntu-latest, CC=clang CXX=clang++, openssl, libusb-1.0)	4m 57s
Analyze (cpp, ubuntu-latest, CC=clang CXX=clang++, openssl, libusb-0.1)	4m 58s
Analyze (python, ubuntu-latest, PYTHON=python3, no, no)	1m 11s
	1h 34m 55s

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