RFR: 8274785: ciReplay: Potential crash due to uninitialized Compile::_ilt variable

[Christian Hagedorn]

While working on JDK-8272912 and inserting `assert(false)` on various places for testing purposes, I noticed the following segmentation fault in one case:

The inline tree `Compile::_ilt` variable is not initialized directly by the initializer list but only later in `Compile::Compile()` when calling 

_ilt = InlineTree::build_inline_tree_root();

Before this assignment, `_ilt` can contain garbage (i.e. `!= NULL`). When hitting an assert or crash before returning from `build_inline_tree_root()`, replay compilation is trying to dump the inline tree and fails to notice that the inline tree is still uninitialized. This can result in a segmentation fault when accessing `_ilt`.

Thanks,
Christian

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Commit messages:
 - 8274785: ciReplay: Potential crash due to uninitialized Compile::_ilt variable

Changes: https://git.openjdk.java.net/jdk/pull/5852/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5852&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8274785
  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5852.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5852/head:pull/5852

PR: https://git.openjdk.java.net/jdk/pull/5852