webrtc: use correct cwd for running tests

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

Index: scripts/slave/recipes/webrtc/standalone.expected/client_webrtc_linux_ubsan.json
diff --git a/scripts/slave/recipes/webrtc/standalone.expected/client_webrtc_linux_ubsan.json b/scripts/slave/recipes/webrtc/standalone.expected/client_webrtc_linux_ubsan.json
index 5d9c779515e7386c781105890ef38e69beec7635..2cbaa94e87981f3a37135e482d788129a5d4b376 100644
--- a/scripts/slave/recipes/webrtc/standalone.expected/client_webrtc_linux_ubsan.json
+++ b/scripts/slave/recipes/webrtc/standalone.expected/client_webrtc_linux_ubsan.json
@@ -276,6 +276,7 @@
       "[BUILDER_CACHE]/Linux_UBSan/src/out/Release/audio_decoder_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]/Linux_UBSan",
     "name": "audio_decoder_unittests"
   },
   {
@@ -301,6 +302,7 @@
       "[BUILDER_CACHE]/Linux_UBSan/src/out/Release/common_audio_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]/Linux_UBSan",
     "name": "common_audio_unittests"
   },
   {
@@ -326,6 +328,7 @@
       "[BUILDER_CACHE]/Linux_UBSan/src/out/Release/common_video_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]/Linux_UBSan",
     "name": "common_video_unittests"
   },
   {
@@ -351,6 +354,7 @@
       "[BUILDER_CACHE]/Linux_UBSan/src/out/Release/modules_tests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]/Linux_UBSan",
     "name": "modules_tests"
   },
   {
@@ -376,6 +380,7 @@
       "[BUILDER_CACHE]/Linux_UBSan/src/out/Release/modules_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]/Linux_UBSan",
     "name": "modules_unittests"
   },
   {
@@ -401,6 +406,7 @@
       "[BUILDER_CACHE]/Linux_UBSan/src/out/Release/peerconnection_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]/Linux_UBSan",
     "name": "peerconnection_unittests"
   },
   {
@@ -426,6 +432,7 @@
       "[BUILDER_CACHE]/Linux_UBSan/src/out/Release/rtc_media_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]/Linux_UBSan",
     "name": "rtc_media_unittests"
   },
   {
@@ -451,6 +458,7 @@
       "[BUILDER_CACHE]/Linux_UBSan/src/out/Release/rtc_pc_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]/Linux_UBSan",
     "name": "rtc_pc_unittests"
   },
   {
@@ -476,6 +484,7 @@
       "[BUILDER_CACHE]/Linux_UBSan/src/out/Release/rtc_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]/Linux_UBSan",
     "name": "rtc_unittests"
   },
   {
@@ -501,6 +510,7 @@
       "[BUILDER_CACHE]/Linux_UBSan/src/out/Release/system_wrappers_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]/Linux_UBSan",
     "name": "system_wrappers_unittests"
   },
   {
@@ -526,6 +536,7 @@
       "[BUILDER_CACHE]/Linux_UBSan/src/out/Release/test_support_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]/Linux_UBSan",
     "name": "test_support_unittests"
   },
   {
@@ -551,6 +562,7 @@
       "[BUILDER_CACHE]/Linux_UBSan/src/out/Release/tools_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]/Linux_UBSan",
     "name": "tools_unittests"
   },
   {
@@ -576,6 +588,7 @@
       "[BUILDER_CACHE]/Linux_UBSan/src/out/Release/video_engine_tests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]/Linux_UBSan",
     "name": "video_engine_tests"
   },
   {
@@ -601,6 +614,7 @@
       "[BUILDER_CACHE]/Linux_UBSan/src/out/Release/voice_engine_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]/Linux_UBSan",
     "name": "voice_engine_unittests"
   },
   {
@@ -626,6 +640,7 @@
       "[BUILDER_CACHE]/Linux_UBSan/src/out/Release/xmllite_xmpp_unittests",
       "--"
     ],
+    "cwd": "[BUILDER_CACHE]/Linux_UBSan",
     "name": "xmllite_xmpp_unittests"
   },
   {
@@ -653,6 +668,7 @@
       "--revision=f27fede2220bcd326aee3e86ddfd4ebd0fe58cb9",
       "webrtc_nonparallel_tests"
     ],
+    "cwd": "[BUILDER_CACHE]/Linux_UBSan",
     "name": "webrtc_nonparallel_tests"
   },
   {