RFR: 8354625: Compile::igv_print_graph_to_network doesn't use its second parameter

[Marc Chevalier]

Remove the second (unused) parameter of `Compile::igv_print_graph_to_network`. It also makes it more consistent with `Compile::igv_print_method_to_file` that always print from root.

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Commit messages:
 - Remove unused parameter

Changes: https://git.openjdk.org/jdk/pull/24675/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24675&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8354625
  Stats: 4 lines in 3 files changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/24675.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24675/head:pull/24675

PR: https://git.openjdk.org/jdk/pull/24675