add daily github actions with libc malloc and valgrind

* fix memlry leaks with diskless replica short read.
* fix a few timing issues with valgrind runs
* fix issue with valgrind and watchdog schedule signal

about the valgrind WD issue:
the stack trace test in logging.tcl, has issues with valgrind:
==28808== Can't extend stack to 0x1ffeffdb38 during signal delivery for thread 1:
==28808==   too small or bad protection modes

it seems to be some valgrind bug with SA_ONSTACK.
SA_ONSTACK seems unneeded since WD is not recursive (SA_NODEFER was removed),
also, not sure if it's even valid without a call to sigaltstack()

.github/workflows/daily.yml

@@ -0,0 +1,48 @@
+name: Daily
+
+on:
+  schedule:
+    - cron: '0 7 * * *'
+
+jobs:
+  test-jemalloc:
+    runs-on: ubuntu-latest
+    timeout-minutes: 1200
+    steps:
+    - uses: actions/checkout@v1
+    - name: make
+      run: make
+    - name: test
+      run: |
+        sudo apt-get install tcl8.5
+        ./runtest --accurate --verbose
+    - name: module api test
+      run: ./runtest-moduleapi --verbose
+
+  test-libc-malloc:
+    runs-on: ubuntu-latest
+    timeout-minutes: 1200
+    steps:
+    - uses: actions/checkout@v1
+    - name: make
+      run: make MALLOC=libc
+    - name: test
+      run: |
+        sudo apt-get install tcl8.5
+        ./runtest --accurate --verbose
+    - name: module api test
+      run: ./runtest-moduleapi --verbose
+
+  test-valgrind:
+    runs-on: ubuntu-latest
+    timeout-minutes: 14400
+    steps:
+    - uses: actions/checkout@v1
+    - name: make
+      run: make valgrind
+    - name: test
+      run: |
+        sudo apt-get install tcl8.5 valgrind -y
+        ./runtest --valgrind --verbose --clients 1
+    - name: module api test
+      run: ./runtest-moduleapi --valgrind --verbose --clients 1