set TOP in sytest containers

.coveragerc

@@ -1,8 +1,8 @@
 [run]
 branch = True
 parallel = True
-include=$GITHUB_WORKSPACE/synapse/*
-data_file = $GITHUB_WORKSPACE/.coverage
+include=$TOP/synapse/*
+data_file = $TOP/.coverage
 
 [report]
 precision = 2

.github/workflows/tests.yml

@@ -200,6 +200,7 @@ jobs:
         WORKERS: ${{ matrix.workers && 1 }}
         REDIS: ${{ matrix.redis && 1 }}
         BLACKLIST: ${{ matrix.workers && 'synapse-blacklist-with-workers' }}
+        TOP: ${{ github.workspace }}
 
     strategy:
       fail-fast: false