RFR: 8350668: has_extra_module_paths in filemap.cpp may be uninitialized

[Ioi Lam]

Please review this trivial patch. The `has_extra_module_paths` local variable should be initialized to `false`.

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Commit messages:
 - 8350668: has_extra_module_paths in filemap.cpp may be uninitialized

Changes: https://git.openjdk.org/jdk/pull/23780/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23780&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8350668
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/23780.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23780/head:pull/23780

PR: https://git.openjdk.org/jdk/pull/23780