RFR: 8283997: Unused argument in GraphKit::builtin_throw

[Tobias Hartmann]

Trivial fix that removes an unused argument and adjust a comment accordingly.

Thanks,
Tobias

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Commit messages:
 - 8283997: Unused argument in GraphKit::builtin_throw

Changes: https://git.openjdk.java.net/jdk/pull/8038/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8038&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8283997
  Stats: 7 lines in 2 files changed: 0 ins; 4 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8038.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8038/head:pull/8038

PR: https://git.openjdk.java.net/jdk/pull/8038