refactor(ci): improve toolchain handling in local-ci workflow

Enhanced the utils.sh script, used by local-ci, to support runtime
fetching of toolchains.

The previously shared toolchain distribution via the SSHFS-mounted /arm
directory has been deprecated. Now, if the toolchain is not available
locally, it will be downloaded from the ARM downloads and extracted
into the workspace directory.

This change ensures consistent builds by aligning the local environment
with the toolchain used in the main CI setup.

Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
Change-Id: Ifff8ef5fb3ab276dc1a482f8d98ae3f5324f656b
2 files changed