RFR: 8279031: Add API note to ToolProvider about being reusable/reentrant

[Christian Stein]

This commit adds an  API note to ToolProvider about being reusable/reentrant.

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Commit messages:
 - 8286815: Add API note to ToolProvider about being reusable/reentrant

Changes: https://git.openjdk.java.net/jdk/pull/8833/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8833&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8279031
  Stats: 8 lines in 1 file changed: 8 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8833.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8833/head:pull/8833

PR: https://git.openjdk.java.net/jdk/pull/8833