Enable Concurrency ABI verifier test on apple silicon (#63987)

Author: ktoso

test/api-digester/stability-concurrency-abi.test

@@ -42,7 +42,10 @@
 // https://github.com/apple/swift/issues/55803
 // We currently only have a baseline for Intel CPUs on macOS.
 // REQUIRES: OS=macosx
-// REQUIRES: CPU=x86_64
+// REQUIRES: CPU=x86_64 || CPU=arm64
+// NOTE: This test runs both on intel and arm, and so far no differences have been spotted,
+//       so for better developer experience on apple silicon macs at desk we don't require a specific architecture.
+//       If there were to be a case where it fails on one of the platforms, we'd have to potentially split out into an arm baseline file.
 // REQUIRES: concurrency
 
 // The digester can incorrectly register a generic signature change when