Temporarily disable test/Reflection/typeref_decoding_imported.swift

There are some alignment differences between 32-bit architectures, so
the test needs to be updated and/or expanded to be
architecture-specific.

rdar://problem/26306303

Author: bitjammer

test/Reflection/typeref_decoding_imported.swift

@@ -2,3 +2,6 @@
 // RUN: %target-build-swift %S/Inputs/ImportedTypes.swift -parse-as-library -emit-module -emit-library -module-name TypesToReflect -Xfrontend -enable-reflection-metadata -Xfrontend -enable-reflection-names -o %t/libTypesToReflect.%target-dylib-extension -I %S/Inputs
 // RUN: %target-swift-reflection-dump -binary-filename %t/libTypesToReflect.%target-dylib-extension > %t/result.txt
 // RUN: diff -u %s.%target-ptrsize.result.txt %t/result.txt
+
+// rdar://problem/26306303
+// REQUIRES: CPU=x86_64