[Modules] Correct test comment from obsolete earlier version of code. NFC

[graydon]

Summary

Code committed in rL290219 went through a few iterations; test wound up with
stale comment.

[manmanren]

LGTM

Manman

test/Modules/implicit-private-with-different-name.m

 // RUN: rm -rf %t
 
 // Build PCH using A, with adjacent private module APrivate, which winds up being implicitly referenced
 // RUN: %clang_cc1 -verify -fmodules -fimplicit-module-maps -fmodules-cache-path=%t -F %S/Inputs/implicit-private-with-different-name -emit-pch -o %t-A.pch %s
 
-// Use the PCH with no explicit way to resolve PrivateA, still pick it up through MODULE_DIRECTORY reference in PCH control block
+// Use the PCH with no explicit way to resolve APrivate, still pick it up by automatic second-chance search for "A" with "Private" appended
 // RUN: %clang_cc1 -verify -fmodules -fimplicit-module-maps -fmodules-cache-path=%t -F %S/Inputs/implicit-private-with-different-name -include-pch %t-A.pch %s -fsyntax-only
 
 // Check the fixit
 // RUN: %clang_cc1  -fmodules -fimplicit-module-maps -fmodules-cache-path=%t -F %S/Inputs/implicit-private-with-different-name -include-pch %t-A.pch %s -fsyntax-only -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
 
 // expected-warning@Inputs/implicit-private-with-different-name/A.framework/Modules/module.private.modulemap:1{{top-level module 'APrivate' in private module map, expected a submodule of 'A'}}
 // expected-note@Inputs/implicit-private-with-different-name/A.framework/Modules/module.private.modulemap:1{{make 'APrivate' a submodule of 'A' to ensure it can be found by name}}
 // CHECK: fix-it:"{{.*}}module.private.modulemap":{1:18-1:26}:"A.Private"
 
 #ifndef HEADER
 #define HEADER
 #import "A/aprivate.h"
 const int *y = &APRIVATE;
 #endif