Add the MultiprocessExec test and its test

util/util.gyp

Index: util/util.gyp
diff --git a/util/util.gyp b/util/util.gyp
index 7d3cf9f052117ced3d5060bd8a256b858a09e1d8..08eef3829a991d44faabb67f80b215ba203cf609 100644
--- a/util/util.gyp
+++ b/util/util.gyp
@@ -100,12 +100,16 @@
       'sources': [
         'test/errors.cc',
         'test/errors.h',
+        'test/executable_path.h',
+        'test/executable_path_mac.cc',
         'test/mac/mach_errors.cc',
         'test/mac/mach_errors.h',
         'test/mac/mach_multiprocess.cc',
         'test/mac/mach_multiprocess.h',
         'test/multiprocess.cc',
         'test/multiprocess.h',
+        'test/multiprocess_exec.cc',
+        'test/multiprocess_exec.h',
         'test/posix/close_multiple.cc',
         'test/posix/close_multiple.h',
       ],
@@ -144,9 +148,18 @@
         'posix/process_util_test.cc',
         'stdlib/strlcpy_test.cc',
         'stdlib/strnlen_test.cc',
+        'test/executable_path_test.cc',
         'test/mac/mach_multiprocess_test.cc',
+        'test/multiprocess_exec_test.cc',
         'test/multiprocess_test.cc',
       ],
     },
+    {
+      'target_name': 'util_test_multiprocess_exec_test_child',
+      'type': 'executable',
+      'sources': [
+        'test/multiprocess_exec_test_child.cc',
+      ],
+    },
   ],
 }