RFR: 8281175: Add a -providerPath option to jarsigner

[Weijun Wang]

Add the `-providerPath` option to jarsigner to be consistent with keytool.

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Commit messages:
 - 8281175: Add a -providerPath option to jarsigner

Changes: https://git.openjdk.java.net/jdk/pull/7338/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7338&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8281175
  Stats: 39 lines in 3 files changed: 24 ins; 5 del; 10 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7338.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7338/head:pull/7338

PR: https://git.openjdk.java.net/jdk/pull/7338