Update radar number in DebugInfo test

The current radar tracking this disabled test is rdar://problem/47777473
See also the similar change on master-next in
#22484

Author: bob-wilson

test/DebugInfo/local-vars.swift.gyb

@@ -2,7 +2,7 @@
 // test only verifies that the variables show up in the debug info at
 // all. There are other tests testing liveness and representation.
 
-// REQUIRES: rdar45708367
+// REQUIRES: rdar47777473
 // RUN: %gyb %s -o %t.swift
 // RUN: %target-swift-frontend %t.swift -g -emit-ir -o - | %FileCheck %t.swift
 // RUN: %target-swift-frontend %t.swift -g -c -o %t.o