[NFC] Add bugs.swift.org links to disabled tests to track re-enabling.

Author: hborla

test/Concurrency/Runtime/executor_deinit1.swift

@@ -4,6 +4,7 @@
 // REQUIRES: concurrency
 // REQUIRES: libdispatch
 
+// https://bugs.swift.org/browse/SR-14461
 // UNSUPPORTED: linux
 
 

validation-test/SILOptimizer/large_string_array.swift.gyb

@@ -1,6 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %gyb %s > %t/main.swift
 
+// https://bugs.swift.org/browse/SR-14460
 // UNSUPPORTED: linux
 
 // The compiler should finish in less than 1 minute. To give some slack,