Disable layout_string_witnesses_dynamic.swift

rdar://151476435

The test is currently crashing on Amazon Linux 2, so until we have a solution, we are disabling it.

Author: drexin

test/Interpreter/layout_string_witnesses_dynamic.swift

@@ -16,6 +16,9 @@
 // UNSUPPORTED: use_os_stdlib
 // UNSUPPORTED: back_deployment_runtime
 
+// test disabled until rdar://151476435 is fixed
+// REQUIRES: rdar://151476435
+
 import Swift
 import layout_string_witnesses_types
 import layout_string_witnesses_types_resilient