filter_multiline: fixed memory leak (CID 508221) #4655

Job	Run time
pr-windows-build / Determine build info	6s
pr-windows-build / call-build-windows-package (Windows 32bit, x86, C:\vcpkg\packages\openssl_x86-windows-static, x86...	21m 5s
pr-windows-build / call-build-windows-package (Windows 64bit, x64, C:\vcpkg\packages\openssl_x64-windows-static, x64...	18m 43s
pr-windows-build / call-build-windows-package (Windows 64bit (Arm64), amd64_arm64, C:\vcpkg\packages\openssl_arm64-w...	20m 35s
pr-windows-build / Handle upload to S3	8s
run-windows-unit-tests / call-build-windows-unit-test (Windows 32bit, x86, C:\vcpkg\packages\openssl_x86-windows-static, x...	19m 36s
run-windows-unit-tests / call-build-windows-unit-test (Windows 64bit, x64, C:\vcpkg\packages\openssl_x64-windows-static, x...	20m 1s
	1h 40m 14s

Provide feedback