RFR: 8261931: IGV: quick search fails on multi-line node labels

[Roberto Castañeda Lozano]

This change makes it possible to match any field of a multi-line node label, by removing line breaks from the `label` node property that is searched on by default.

Tested manually using different node label configurations (configurable in `Tools` -> `Options` -> `General`), with and without line breaks.

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Commit messages:
 - 8261931: IGV: quick search fails on multi-line node labels

Changes: https://git.openjdk.java.net/jdk/pull/2889/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2889&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8261931
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2889.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2889/head:pull/2889

PR: https://git.openjdk.java.net/jdk/pull/2889