RFR: 8271140: Fix native frame handling in vframeStream::asJavaVFrame()

[Vladimir Kozlov]

On Thu, 22 Jul 2021 13:07:46 GMT, Andreas Woess <aw at openjdk.org> wrote:

> Follow-up to https://github.com/openjdk/jdk/pull/4625 ([JDK-8269592](https://bugs.openjdk.java.net/browse/JDK-8269592)) which added support for native frames to `vframeStreamCommon::asJavaVFrame()`. This change was not correct when `asJavaVFrame()` is called for a native frame that is the last frame on the stack (i.e. the first frame in the stream), in which case there's no `_prev_frame` yet. We don't actually need the extended frame information for native frames, so the fix is to just use the vframeStream's `_frame` and `_reg_map` for native frames.
> Extended the test from JDK-8269592 to cover this case.

Testing show failures. Please, investigate.

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Changes requested by kvn (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/4872