RFR: 8360304: Redundant condition in LibraryCallKit::inline_vector_nary_operation

[Francesco Andreuzzi]

The check for `sopc != 0` is not needed after JDK-8353786, the function would exit at L374 otherwise.

Passes tier1.

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Commit messages:
 - remove redundant check

Changes: https://git.openjdk.org/jdk/pull/26606/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26606&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8360304
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/26606.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26606/head:pull/26606

PR: https://git.openjdk.org/jdk/pull/26606