RFR: 8303082 : [AIX] Missing C++ name demangling with XLClang++

[Deepa Kumari]

It was failing as It was using the C++ demangling interface (Demangle) of the old demangler (that is, the C++ API as opposed to the C one). It is not supported by xlclang++ on AIX.
To demangle names generated by xlclang++ , use cxxabi.h __cxa_demangle interface ( see cxxabi.h).

This Solution applies to the following test 

1. SecondaryErrorTest.java`
2. TestSigInfoInHsErrFile.java


Reported Issue : [JDK - 8303082](https://bugs.openjdk.org/browse/JDK-8303082)

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Commit messages:
 - 8303082 : [AIX] Missing C++ name demangling with XLClang++

Changes: https://git.openjdk.org/jdk/pull/12742/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12742&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8303082
  Stats: 22 lines in 1 file changed: 0 ins; 14 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/12742.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12742/head:pull/12742

PR: https://git.openjdk.org/jdk/pull/12742