Previously, we used `aarch64` as platform names in cockroachdb binary
and release archive names. This has been problematic, because we use
`runtime.GOARCH` (`arm64`) in many places. Fixing usages would be
problematic, because we would need to create special cases for the ARM64
platform.

Additionally, the linux binaries and release archives contain the minimum
supported kernel version. This also creates a special case. Given that
we have not bumped the linux kernel version requirement for ARM64, we
can omit the kernel version in the names.

Additionally, to make the upgrade tests work, we need to copy the
already published release tarballs using the new naming schema.

Epic: none
Fixes: #94441

Release note: None