RFR: 8278367: JNI critical region violation in CTextPipe.m:363

[Phil Race]

This re-jigs some lines of code so that we do all the lookups of the arrays before calling the GetPrimitiveArrayCritical on both of them together. Thereby avoiding warnings about calling those other methods in that context.

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Commit messages:
 - 8278367

Changes: https://git.openjdk.java.net/jdk/pull/8506/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8506&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8278367
  Stats: 11 lines in 1 file changed: 9 ins; 2 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8506.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8506/head:pull/8506

PR: https://git.openjdk.java.net/jdk/pull/8506