Collect JVM crashes in circleci artifacts

So we could investigate them later.

.circleci/collect_reports.sh

@@ -8,6 +8,8 @@ set -e
 REPORTS_DIR=./reports
 mkdir -p $REPORTS_DIR >/dev/null 2>&1
 
+cp /tmp/hs_err_pid*.log $REPORTS_DIR || true
+
 function save_reports () {
     project_to_save=$1
     echo "saving reports for $project_to_save"

dd-trace-java.gradle

@@ -59,5 +59,6 @@ allprojects {
   tasks.withType(JavaForkOptions) {
     maxHeapSize = System.properties["datadog.forkedMaxHeapSize"]
     minHeapSize = System.properties["datadog.forkedMinHeapSize"]
+    jvmArgs "-XX:ErrorFile=/tmp/hs_err_pid%p.log"
   }
 }