Separate CI building and testing steps, and increase max memory.

Gradle was using too much memory when testing and building in the same
step, causing CI to kill the process forcefully. Separating them out
resolves the problem.

.circleci/config.yml

@@ -12,9 +12,13 @@ jobs:
           # Reset the cache approx every release
           key: dd-trace-java-{{ checksum "dd-trace-java.gradle" }}
 
+      - run:
+          name: Build Project
+          command: GRADLE_OPTS="-Dorg.gradle.jvmargs=-Xmx2G -Xms512M" ./gradlew clean compileJava compileTestJava compileGroovy compileTestGroovy shadowJar --stacktrace --no-daemon
+
       - run:
           name: Run Tests
-          command: GRADLE_OPTS="-Dorg.gradle.jvmargs=-Xmx1G -Xms512M" ./gradlew clean check --parallel --stacktrace --no-daemon --max-workers=3
+          command: GRADLE_OPTS="-Dorg.gradle.jvmargs=-Xmx2G -Xms512M" ./gradlew check --parallel --stacktrace --no-daemon --max-workers=3
 
       - run:
           name: Verify Version Scan