[lit/libcxx] Fix a remaining reference to lit.util.capture() in custom libcxx/Darwin code.

Summary:
This reference to lit.util.capture is functionally identical to
subprocess.check_output, so this change switches to call the library routine
directly.

Reviewers: mzolotukhin, EricWF

Reviewed By: mzolotukhin

Subscribers: sanjoy, llvm-commits

Differential Revision: https://reviews.llvm.org/D34841

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@306755 91177308-0d34-0410-b5e6-96231b3b80d8

utils/libcxx/test/target_info.py

@@ -8,11 +8,11 @@
 #===----------------------------------------------------------------------===//
 
 import importlib
-import lit.util  # pylint: disable=import-error,no-name-in-module
 import locale
 import os
 import platform
 import re
+import subprocess
 import sys
 
 class DefaultTargetInfo(object):
@@ -73,12 +73,13 @@ class DarwinLocalTI(DefaultTargetInfo):
         super(DarwinLocalTI, self).__init__(full_config)
 
     def is_host_macosx(self):
-        name = lit.util.capture(['sw_vers', '-productName']).strip()
+        name = subprocess.check_output(['sw_vers', '-productName']).strip()
         return name == "Mac OS X"
 
     def get_macosx_version(self):
         assert self.is_host_macosx()
-        version = lit.util.capture(['sw_vers', '-productVersion']).strip()
+        version = subprocess.check_output(
+            ['sw_vers', '-productVersion']).strip()
         version = re.sub(r'([0-9]+\.[0-9]+)(\..*)?', r'\1', version)
         return version
 
@@ -86,7 +87,7 @@ class DarwinLocalTI(DefaultTargetInfo):
         assert self.is_host_macosx()
         cmd = ['xcrun', '--sdk', name, '--show-sdk-path']
         try:
-            out = lit.util.capture(cmd).strip()
+            out = subprocess.check_output(cmd).strip()
         except OSError:
             pass
 
@@ -127,7 +128,7 @@ class DarwinLocalTI(DefaultTargetInfo):
         else:
             cmd = ['xcrun', '--show-sdk-path']
         try:
-            out = lit.util.capture(cmd).strip()
+            out = subprocess.check_output(cmd).strip()
             res = 0
         except OSError:
             res = -1