RFR: 8251188: Update LDAP tests not to use wildcard addresses

[Aleksei Efimov]

Hi,

Please help to review [JDK-8251188](https://bugs.openjdk.java.net/browse/JDK-8251188) fix which helps to improve LDAP
tests stability. The list of changes: 1. Usages of wildcard address have been replaced with loopback address. This
change includes addition of `LDAPTestUtils.initEnv` method that takes LDAP provider URL as a parameter. 2.
`DeadServerTimeoutSSLTest.java` was also updated to fix the intermittent failures reported by [JDK-8152654
](https://bugs.openjdk.java.net/browse/JDK-8152654) and
[JDK-8169942](https://bugs.openjdk.java.net/browse/JDK-8169942). Before the fix the failure rate was 1 out of 4 runs.
After the fix it was executed 400+ times alongside to other LDAP tests, and showed no failures, and therefore removed
from the problem list.

Thank you,
Aleksei

-------------

Commit messages:
 - 8251188: Update LDAP tests not to use wildcard addresses

Changes: https://git.openjdk.java.net/jdk/pull/252/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=252&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8251188
  Stats: 149 lines in 5 files changed: 76 ins; 28 del; 45 mod
  Patch: https://git.openjdk.java.net/jdk/pull/252.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/252/head:pull/252

PR: https://git.openjdk.java.net/jdk/pull/252