RFR: JDK-8266676: G1: Remove dead code init_node_id_to_index_map()

[Hamlin Li]

This is a trivial change to remove some dead code in G1 Numa.

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Commit messages:
 - Merge branch 'openjdk:master' into remove-g1NUMA
 - JDK-8266676: G1: Remove dead code init_node_id_to_index_map()

Changes: https://git.openjdk.java.net/jdk/pull/3962/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3962&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8266676
  Stats: 4 lines in 1 file changed: 0 ins; 3 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3962.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3962/head:pull/3962

PR: https://git.openjdk.java.net/jdk/pull/3962