[ASTERIXDB-3144][RT] Make index modification runtime support multiple partitions

- user model changes: no
- storage format changes: no
- interface changes: yes

Details:
This patch changes the index modification runtime to support
operating on multiple partitions. With this change, an index
modification node pushable will write to multiple indexes
representing multiple partitions. This is a step towards
achieving compute/storage separation.

Change-Id: I08da28f2a26fcaf581c2256312455fe541fae5ea
Reviewed-on: https://asterix-gerrit.ics.uci.edu/c/asterixdb/+/17452
Integration-Tests: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Reviewed-by: Murtadha Hubail <mhubail@apache.org>
diff --git a/hyracks-fullstack/hyracks/hyracks-storage-am-lsm-common/pom.xml b/hyracks-fullstack/hyracks/hyracks-storage-am-lsm-common/pom.xml
index d8d155e..ba932e1 100644
--- a/hyracks-fullstack/hyracks/hyracks-storage-am-lsm-common/pom.xml
+++ b/hyracks-fullstack/hyracks/hyracks-storage-am-lsm-common/pom.xml
@@ -94,5 +94,9 @@
       <groupId>com.fasterxml.jackson.core</groupId>
       <artifactId>jackson-databind</artifactId>
     </dependency>
+    <dependency>
+      <groupId>it.unimi.dsi</groupId>
+      <artifactId>fastutil-core</artifactId>
+    </dependency>
   </dependencies>
 </project>
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