Bug 1845098 - Add the HeapDumpOnOutOfMemoryError default to jvmargs

According to https://github.com/gradle/gradle/issues/19750 setting the org.gradle.jvmargs property can lead to "Daemon disappeared" failures
by removing the default values.
Also use -XX:+UseParallelGC to improve build performance.

gradle.properties

@@ -10,7 +10,7 @@
 # http://www.gradle.org/docs/current/userguide/build_environment.html
 # Specifies the JVM arguments used for the daemon process.
 # The setting is particularly useful for tweaking memory settings.
-org.gradle.jvmargs=-Xmx7g -Xms2g -XX:MaxMetaspaceSize=6g
+org.gradle.jvmargs=-Xmx7g -Xms2g -XX:MaxMetaspaceSize=6g -XX:+HeapDumpOnOutOfMemoryError -XX:+UseParallelGC
 # When configured, Gradle will run in incubating parallel mode.
 # This option should only be used with decoupled projects. More details, visit
 # http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects