[Modules] Test lock file removed on signal

For r240967.

rdar://problem/21512307

llvm-svn: 240968

clang/test/Modules/Inputs/crash.h

@@ -0,0 +1 @@
+#pragma clang __debug crash

clang/test/Modules/Inputs/module.map

@@ -324,3 +324,6 @@ module recursive1 {
 module recursive2 {
   header "recursive2.h"
 }
+module crash {
+  header "crash.h"
+}

clang/test/Modules/signal.m

@@ -0,0 +1,11 @@
+// REQUIRES: shell
+// RUN: rm -rf %t
+
+// Crash building module.
+// RUN: not --crash %clang_cc1 -fmodules -fimplicit-module-maps -fmodules-cache-path=%t -I%S/Inputs %s
+
+// The dead symlink is still around, but the underlying lock file is gone.
+// RUN: find %t -name "crash-*.pcm.lock" | count 1
+// RUN: find %t -name "crash-*.pcm.lock-*" | count 0
+
+@import crash;