RFR: 8293489: Accept CAs with BasicConstraints without pathLenConstraint

[Weijun Wang]

Provide a new test for an old bug fix.

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Commit messages:
 - new test

Changes: https://git.openjdk.org/jdk/pull/10203/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10203&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8293489
  Stats: 80 lines in 1 file changed: 80 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/10203.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10203/head:pull/10203

PR: https://git.openjdk.org/jdk/pull/10203