webrtc: use correct cwd for running tests

scripts/slave/recipes/webrtc/standalone.expected/client_webrtc_win64_release.json

Index: scripts/slave/recipes/webrtc/standalone.expected/client_webrtc_win64_release.json
diff --git a/scripts/slave/recipes/webrtc/standalone.expected/client_webrtc_win64_release.json b/scripts/slave/recipes/webrtc/standalone.expected/client_webrtc_win64_release.json
index d555151745465abfb8f0745eaf41cc008319ec80..0935c2fcb2cfd9066ec0bbc6ad29da2c8cda0866 100644
--- a/scripts/slave/recipes/webrtc/standalone.expected/client_webrtc_win64_release.json
+++ b/scripts/slave/recipes/webrtc/standalone.expected/client_webrtc_win64_release.json
@@ -229,6 +229,7 @@
       "[BUILDER_CACHE]\\Win64_Release\\src\\out\\Release_x64\\audio_decoder_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]\\Win64_Release",
     "name": "audio_decoder_unittests"
   },
   {
@@ -253,6 +254,7 @@
       "[BUILDER_CACHE]\\Win64_Release\\src\\out\\Release_x64\\common_audio_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]\\Win64_Release",
     "name": "common_audio_unittests"
   },
   {
@@ -277,6 +279,7 @@
       "[BUILDER_CACHE]\\Win64_Release\\src\\out\\Release_x64\\common_video_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]\\Win64_Release",
     "name": "common_video_unittests"
   },
   {
@@ -301,6 +304,7 @@
       "[BUILDER_CACHE]\\Win64_Release\\src\\out\\Release_x64\\modules_tests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]\\Win64_Release",
     "name": "modules_tests"
   },
   {
@@ -325,6 +329,7 @@
       "[BUILDER_CACHE]\\Win64_Release\\src\\out\\Release_x64\\modules_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]\\Win64_Release",
     "name": "modules_unittests"
   },
   {
@@ -349,6 +354,7 @@
       "[BUILDER_CACHE]\\Win64_Release\\src\\out\\Release_x64\\peerconnection_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]\\Win64_Release",
     "name": "peerconnection_unittests"
   },
   {
@@ -373,6 +379,7 @@
       "[BUILDER_CACHE]\\Win64_Release\\src\\out\\Release_x64\\rtc_media_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]\\Win64_Release",
     "name": "rtc_media_unittests"
   },
   {
@@ -397,6 +404,7 @@
       "[BUILDER_CACHE]\\Win64_Release\\src\\out\\Release_x64\\rtc_pc_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]\\Win64_Release",
     "name": "rtc_pc_unittests"
   },
   {
@@ -421,6 +429,7 @@
       "[BUILDER_CACHE]\\Win64_Release\\src\\out\\Release_x64\\rtc_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]\\Win64_Release",
     "name": "rtc_unittests"
   },
   {
@@ -445,6 +454,7 @@
       "[BUILDER_CACHE]\\Win64_Release\\src\\out\\Release_x64\\system_wrappers_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]\\Win64_Release",
     "name": "system_wrappers_unittests"
   },
   {
@@ -469,6 +479,7 @@
       "[BUILDER_CACHE]\\Win64_Release\\src\\out\\Release_x64\\test_support_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]\\Win64_Release",
     "name": "test_support_unittests"
   },
   {
@@ -493,6 +504,7 @@
       "[BUILDER_CACHE]\\Win64_Release\\src\\out\\Release_x64\\tools_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]\\Win64_Release",
     "name": "tools_unittests"
   },
   {
@@ -517,6 +529,7 @@
       "[BUILDER_CACHE]\\Win64_Release\\src\\out\\Release_x64\\video_engine_tests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]\\Win64_Release",
     "name": "video_engine_tests"
   },
   {
@@ -541,6 +554,7 @@
       "[BUILDER_CACHE]\\Win64_Release\\src\\out\\Release_x64\\voice_engine_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]\\Win64_Release",
     "name": "voice_engine_unittests"
   },
   {
@@ -565,6 +579,7 @@
       "[BUILDER_CACHE]\\Win64_Release\\src\\out\\Release_x64\\xmllite_xmpp_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]\\Win64_Release",
     "name": "xmllite_xmpp_unittests"
   },
   {
@@ -591,6 +606,7 @@
       "--revision=f27fede2220bcd326aee3e86ddfd4ebd0fe58cb9",
       "webrtc_nonparallel_tests.exe"
     ],
+    "cwd": "[BUILDER_CACHE]\\Win64_Release",
     "name": "webrtc_nonparallel_tests"
   },
   {