RFR: 8276990: Memory leak in invoker.c fillInvokeRequest() during JDI operations [v2]

[Roman Kennke]

> We observe a native memory leak when repeating JDI operations from Eclipse in a debuggee JVM. See bug report for details.
> 
> AFAICT, this happens because we override methodSignature of a possible pre-existing request object. I am not sure if there is a better place to deallocate the signature.
> 
> Also, I am not sure how to make an automated test for this. We (that is, the customer that reported the problem) verified that the memory leak disappears with the fix.

Roman Kennke has updated the pull request incrementally with one additional commit since the last revision:

  Deallocate methodSignature after completed request

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7306/files
  - new: https://git.openjdk.java.net/jdk/pull/7306/files/52eac5b2..4b62941b

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7306&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7306&range=00-01

  Stats: 8 lines in 1 file changed: 4 ins; 3 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7306.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7306/head:pull/7306

PR: https://git.openjdk.java.net/jdk/pull/7306