Auto merge of #131362 - Kobzol:ci-free-runners-linux-4c, r=Mark-Simul…

…acrum

CI: use free runners for 4-core Linux jobs

It looks like the [free runners](https://docs.github.com/en/actions/using-github-hosted-runners/using-github-hosted-runners/about-github-hosted-runners#standard-github-hosted-runners-for-public-repositories) already have the same spec as the `4c` custom "large" runner (4 cores, 16 GiB of memory, Ubuntu 20.04).

try-job: arm-android
try-job: armhf-gnu
try-job: dist-aarch64-linux
try-job: dist-android
try-job: dist-arm-linux
try-job: dist-armhf-linux
try-job: dist-armv7-linux
try-job: dist-i586-gnu-i586-i686-musl
try-job: dist-i686-linux
try-job: dist-loongarch64-linux
try-job: dist-loongarch64-musl
try-job: dist-ohos
try-job: dist-powerpc-linux
try-job: dist-powerpc64-linux
try-job: dist-powerpc64le-linux
try-job: dist-riscv64-linux
try-job: dist-s390x-linux
try-job: dist-various-1
try-job: dist-various-2
try-job: dist-x86_64-freebsd
try-job: dist-x86_64-illumos
try-job: dist-x86_64-netbsd
try-job: mingw-check
try-job: test-various
try-job: x86_64-gnu
try-job: x86_64-gnu-stable
try-job: x86_64-gnu-aux
try-job: x86_64-gnu-debug
try-job: x86_64-gnu-nopt