Fix handling of testResult in tpm2_gettestresult #1808

Job	Run time
coverity-test	0s
master-tss-build-test (gcc)	18m 4s
coverage-test	6m 30s
build-test (ubuntu-20.04, gcc)	5m 55s
master-tss-build-test (clang)	4m 55s
build-test (ubuntu-20.04, clang)	4m 55s
build-test (fedora-30, gcc)	5m 53s
build-test (fedora-30, clang)	5m 25s
build-test (opensuse-leap, gcc)	6m 6s
build-test (opensuse-leap, clang)	5m 18s
build-test (fedora-32, gcc)	5m 57s
build-test (fedora-32, clang)	5m 12s
build-test (ubuntu-22.04, gcc)	11m 31s
build-test (ubuntu-22.04, clang)	10m 55s
	1h 36m 36s

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