Use absolute path to fix xunit result upload in Evergreen

Author: alcaeus

.evergreen/config.yml

@@ -164,7 +164,9 @@ functions:
   "upload test results":
     - command: attach.xunit_results
       params:
-        file: "${PROJECT_DIRECTORY}/test-results.xml"
+        # Uploading test results does not work when using ${PROJECT_DIRECTORY},
+        # so we use an absolute path to work around this
+        file: "src/test-results.xml"
     - command: attach.results
       params:
         file_location: "${DRIVERS_TOOLS}/results.json"