Rename the aarch64 sha1sums file to sha1sums-aarch64-common to follow
the same naming convention as sha1sums-x86_64-common. This allows
run_metrics.sh to use the generic sha1sums-${TEST_ARCH}-common
pattern for all architectures, removing the need for aarch64-specific
conditionals.
Update run_integration_tests_aarch64.sh to reference the renamed file.
Signed-off-by: Souradeep <schakrabarti@microsoft.com>