Add non-empty vars #2539

Job	Run time
linux-compat (manylinux1-x64)	1m 11s
linux-compiler-compat (clang-3)	2m 0s
linux-compat (manylinux1-x86)	1m 10s
linux-compiler-compat (clang-6)	6m 13s
linux-compat (manylinux2014-x64)	1m 19s
linux-compiler-compat (clang-8)	6m 39s
linux-compat (manylinux2014-x86)	1m 20s
linux-compiler-compat (clang-9)	6m 0s
linux-compat (raspbian-bullseye)	7m 4s
linux-compiler-compat (clang-10)	1m 47s
linux-compat (fedora-34-x64)	1m 15s
linux-compiler-compat (clang-11)	1m 54s
linux-compat (opensuse-leap)	1m 26s
linux-compat (rhel8-x64)	1m 7s
linux-compiler-compat (gcc-4.8)	1m 51s
clang-sanitizers (,thread)	2m 34s
linux-compat (al2-x64)	1m 7s
linux-compiler-compat (gcc-5)	1m 38s
downstream	45m 13s
clang-sanitizers (,address,undefined)	1m 53s
linux-compiler-compat (gcc-6)	1m 49s
linux-compiler-compat (gcc-7)	1m 42s
linux-shared-libs	1m 43s
linux-compiler-compat (gcc-8)	1m 53s
linux-no-cpu-extensions	1m 36s
windows	2m 39s
linux-compiler-compat (gcc-11)	1m 49s
windows-shared-libs	2m 38s
windows-vc14 (x86)	2m 33s
windows-vc15 (x86)	2m 29s
windows-vc14 (x64)	1m 50s
windows-vc16 (x86)	1m 43s
windows-vc15 (x64)	2m 16s
windows-vc16 (x64)	2m 35s
Cross Compile linux-armv6	1m 54s
Cross Compile linux-armv7	2m 7s
freebsd	9m 29s
macos-no-cpu-extensions	1m 43s
Cross Compile linux-arm64	1m 38s
macos	1m 25s
Cross Compile android-armv7	2m 23s
macos-x64	2m 42s
openbsd	11m 31s
windows-app-verifier	20m 0s
windows-no-cpu-extensions	2m 30s
linux-debug	1m 33s
macos-debug	1m 52s
windows-debug	2m 54s
	3h 7m 37s

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