RFR: 8303413: (fs) Ignore polling interval sensitivity modifiers in PollingWatchService [v2]

[Brian Burkhalter]

> Modify `sun.nio.fs.PollingWatchService` to ignore any polling sensitivity modifiers as done by the other `WatchService`s.

Brian Burkhalter has updated the pull request incrementally with one additional commit since the last revision:

  8303413: Reduce SensitivityModifier test to ensuring no exception on register

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Changes:
  - all: https://git.openjdk.org/jdk/pull/12795/files
  - new: https://git.openjdk.org/jdk/pull/12795/files/2ab63574..be2c1b4c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12795&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12795&range=00-01

  Stats: 48 lines in 1 file changed: 0 ins; 47 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/12795.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12795/head:pull/12795

PR: https://git.openjdk.org/jdk/pull/12795