Fix test to use macOS 12.0 as the first OS to not require autolinking

instead of the notional 10.24, which the old logic in Platform.cpp
accidentally treated as a future release with no runtime restrictions.

Author: rjmccall

test/IRGen/autolink-runtime-compatibility.swift

@@ -8,7 +8,7 @@
 // RUN: %target-swift-frontend -runtime-compatibility-version none -emit-ir -parse-stdlib %s | %FileCheck -check-prefix=NO-FORCE-LOAD %s
 
 // Doesn't autolink compatibility library because target OS doesn't need it
-// RUN: %target-swift-frontend -target %target-cpu-apple-macosx10.24 -emit-ir -parse-stdlib %s | %FileCheck -check-prefix=NO-FORCE-LOAD %s
+// RUN: %target-swift-frontend -target %target-cpu-apple-macosx12.0 -emit-ir -parse-stdlib %s | %FileCheck -check-prefix=NO-FORCE-LOAD %s
 
 // Only autolinks 5.1 compatibility library because target OS has 5.1
 // RUN: %target-swift-frontend -target %target-cpu-apple-macosx10.15 -emit-ir -parse-stdlib %s | %FileCheck -check-prefix=FORCE-LOAD-51 %s