RFR: 8294547: HotSpotAgent.setupVM() should include "cause" exception when throwing DebuggerException

[Chris Plummer]

In `HotSpotAgent.setupVM()`, if there is an underlying exception in the vm setup, the exception is consumed and a `DebuggerException` is thrown, hiding the root cause. When throwing the `DebuggerException`, the "cause" exception should be included. This provides a more detailed exception stack trace, such as the following:


Doesn't appear to be a HotSpot VM (could not find symbol "gHotSpotVMTypes" in
remote process)
sun.jvm.hotspot.debugger.DebuggerException: Doesn't appear to be a HotSpot VM (could not find symbol "gHotSpotVMTypes" in remote process)
at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotAgent.setupVM(HotSpotAgent.java:428)
at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotAgent.go(HotSpotAgent.java:338)
at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotAgent.attach(HotSpotAgent.java:158)
at jdk.hotspot.agent/sun.jvm.hotspot.CLHSDB.attachDebugger(CLHSDB.java:210)
at jdk.hotspot.agent/sun.jvm.hotspot.CLHSDB.run(CLHSDB.java:69)
at jdk.hotspot.agent/sun.jvm.hotspot.CLHSDB.main(CLHSDB.java:44)
at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.runCLHSDB(SALauncher.java:281)
at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.main(SALauncher.java:500)
Caused by: sun.jvm.hotspot.debugger.NoSuchSymbolException: Could not find symbol "gHotSpotVMTypes" in any of the known library names (jvm.dll)
at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotTypeDataBase.lookupInProcess(HotSpotTypeDataBase.java:622)
at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotTypeDataBase.readVMTypes(HotSpotTypeDataBase.java:154)
at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotTypeDataBase.<init>(HotSpotTypeDataBase.java:89)
at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotAgent.setupVM(HotSpotAgent.java:407)
... 7 more 


I'd like to push this as a trivial change.

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Commit messages:
 - Include cause exception

Changes: https://git.openjdk.org/jdk/pull/10474/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10474&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8294547
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/10474.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10474/head:pull/10474

PR: https://git.openjdk.org/jdk/pull/10474