tests: Fix IDL memory leak. #7

Job	Run time
osx clang --disable-ssl	1m 40s
linux rpm fedora	4m 3s
dpdk gcc	7s
linux deb no dpdk	4m 55s
clang-analyze	10m 0s
linux gcc --disable-ssl	2m 15s
linux clang --disable-ssl	2m 40s
linux gcc c99	2m 26s
linux clang c99	2m 25s
linux gcc test	8m 4s
linux clang address,undefined test	16m 32s
linux gcc test --enable-shared	11m 34s
linux clang test --enable-shared	11m 11s
linux gcc check check-dpdk dpdk	18m 20s
linux clang check check-dpdk dpdk	17m 47s
linux gcc test -ljemalloc	8m 28s
linux clang test -ljemalloc	8m 39s
linux gcc --enable-afxdp	2m 31s
linux clang --enable-afxdp	2m 26s
linux gcc dpdk --enable-shared	3m 33s
linux clang dpdk --enable-shared	3m 24s
linux gcc dpdk-shared	3m 8s
linux clang dpdk-shared	2m 49s
linux gcc dpdk-shared --enable-shared	3m 29s
linux clang dpdk-shared --enable-shared	3m 31s
linux gcc m32 --disable-ssl	2m 23s
linux gcc check-ovsdb-cluster	6m 12s
linux gcc check-kernel -100	8m 56s
linux gcc check-kernel 100-	9m 40s
linux clang address,undefined check-kernel -100	11m 15s
linux clang address,undefined check-kernel 100-	12m 11s
linux gcc check-offloads -100	9m 8s
linux gcc check-offloads 100-	7m 19s
linux gcc dpdk check-system-userspace	10m 50s
linux clang address,undefined dpdk check-system-userspace	14m 15s
linux gcc dpdk check-system-tso	10m 40s
linux gcc dpdk check-afxdp	11m 20s
	4h 30m 6s

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