WIP add a bash script for rerunning unit test shard 4 under coverage for troubleshooting

scripts/test_coverage.sh

+#!/usr/bin/env bash
+set -e
+set -vx
+
+
+# Run this with: bash scripts/test_coverage.sh
+
+# Clean up previous builds
+git clean -qxfd
+paver install_prereqs
+rm -rf ../reports_*
+
+export COVERAGE_DEBUG_FILE=reports/coverage_debug.log
+export DISABLE_MIGRATIONS=1
+export NO_PREREQ_INSTALL=1
+
+counter=0
+LIMIT=20
+
+while [ "$counter" -lt "$LIMIT" ]
+do
+  DISABLE_MIGRATIONS=1 paver test_system -s lms --attr='!shard' --with-flaky --processes=-1 --cov-args="-p" --with-xunitmp
+  mv reports "../reports_$counter"
+  counter=`expr $counter + 1`
+done