Remove references to an old gyp variable that's no longer supported.

chrome/browser_tests.isolate

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 {
   'conditions': [
     ['use_x11==0', {
       'variables': {
         'command': [
           '../testing/test_env.py',
           '<(PRODUCT_DIR)/browser_tests<(EXECUTABLE_SUFFIX)',
@@ skipping 32 matching lines @@
       },
     }],
     ['OS=="linux" and branding=="Chrome" and enable_pepper_cdms==1', {
       'variables': {
         'files': [
           '<(PRODUCT_DIR)/libwidevinecdm.so',
           '<(PRODUCT_DIR)/libwidevinecdmadapter.so',
         ],
       },
     }],
-    ['OS=="linux" and libpeer_target_type=="loadable_module"', {
-      'variables': {
-        'files': [
-          '<(PRODUCT_DIR)/lib/libpeerconnection.so',
-        ],
-      },
-    }],
     ['OS=="linux" or OS=="mac" or OS=="win"', {
       'variables': {
         'files': [
           '../content/test/data/',
           '../google_apis/test/',
           '../media/test/data/',
           '../media/test/data/',
           '../net/data/',
           '../net/tools/testserver/',
           '../ppapi/tests/test_case.html',
@@ skipping 191 matching lines @@
           'browser/chromeos/login/test/https_forwarder.py',
         ],
       },
     }],
   ],
   'includes': [
     '../base/base.isolate',
     'chrome.isolate',
   ],
 }