json: Store short arrays in-place. #3275

Job	Run time
dpdk gcc (ubuntu-24.04)	9s
libreswan (ubuntu-24.04)	8s
linux rpm fedora	3m 58s
linux deb no dpdk	4m 44s
build oss-fuzz fuzzers	2m 54s
osx clang --disable-ssl	1m 45s
linux gcc --disable-ssl	2m 35s
clang-analyze-cache	10m 50s
linux clang --disable-ssl	2m 46s
linux gcc c99	2m 45s
linux clang c99	2m 31s
linux gcc test	8m 40s
linux clang address,undefined test	16m 45s
linux gcc test --enable-shared	11m 46s
linux clang test --enable-shared	11m 0s
linux gcc check check-dpdk dpdk	19m 33s
linux clang check check-dpdk dpdk	18m 40s
linux gcc test -ljemalloc	9m 9s
linux clang test -ljemalloc	10m 30s
linux gcc --enable-afxdp	4m 23s
linux clang --enable-afxdp	2m 32s
linux gcc dpdk --enable-shared	3m 47s
linux clang dpdk --enable-shared	3m 48s
linux gcc dpdk-shared	3m 15s
linux clang dpdk-shared	3m 12s
linux gcc dpdk-shared --enable-shared	4m 13s
linux clang dpdk-shared --enable-shared	3m 59s
linux gcc m32 --disable-ssl	4m 6s
linux gcc check-ovsdb-cluster	6m 33s
linux gcc check-kernel -100	10m 51s
linux gcc check-kernel 100-	17m 11s
linux clang address,undefined check-kernel -100	12m 56s
linux clang address,undefined check-kernel 100-	19m 24s
linux gcc check-offloads -100	9m 53s
linux gcc check-offloads 100-	12m 9s
linux gcc dpdk check-system-userspace	12m 43s
linux clang address,undefined dpdk check-system-userspace	16m 15s
linux gcc dpdk check-system-tso	14m 17s
linux gcc dpdk check-afxdp	12m 6s
clang-analyze	10m 29s
	5h 29m 10s

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