chore: flag to disable native toolchain download

Author: sureshg

gradle.properties

@@ -31,6 +31,7 @@ kotlin.incremental.native=true
 kotlin.native.binary.gc=cms
 kotlin.native.ignoreDisabledTargets=true
 kotlin.native.enableKlibsCrossCompilation=true
+# kotlin.native.toolchain.enabled=false
 # kotlin.mpp.enableCInteropCommonization=true
 
 ## Dokka