fix github actions failing latency test for active defrag

seems that github actions are slow, using just one client to reduce
false positives.

also adding verbose, testing only on latest ubuntu, and building on
older one.

when doing that, i can reduce the test threshold back to something saner

.github/workflows/ci.yml

@@ -3,11 +3,8 @@ name: CI
 on: [push, pull_request]
 
 jobs:
-  build-ubuntu:
-    strategy:
-      matrix:
-        platform: [ubuntu-latest, ubuntu-16.04]
-    runs-on: ${{ matrix.platform }}
+  test-ubuntu-latest:
+    runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v1
     - name: make
@@ -15,13 +12,17 @@ jobs:
     - name: test
       run: |
         sudo apt-get install tcl8.5
-        make test
+        ./runtest --clients 1 --verbose
 
+  test-ubuntu-old:
+    runs-on: ubuntu-16.04
+    steps:
+    - uses: actions/checkout@v1
+    - name: make
+      run: make
+
   build-macos-latest:
-    strategy:
-      matrix:
-        platform: [macos-latest, macOS-10.14]
-    runs-on: ${{ matrix.platform }}
+    runs-on: macos-latest
     steps:
     - uses: actions/checkout@v1
     - name: make