RFR: 8274910: Compile in G1 evacuation failure injection code based on define [v2]

[Thomas Schatzl]

> Hi all,
> 
>   can I have reviews for this change that simplifies performance work with evacuation failure handling a little? In particular, it adds a define called `EVAC_FAILURE_INJECTOR` (on by default in non-product builds) that allows to compile in/out the relevant injector code also in product mode (if manually enabled).
> 
> Actually, this PR suggests two variants for this: one that also automatically enables flags when `EVAC_FAILURE_INJECTOR` is selected (beaa6c3), and one that requires the developer also change the options from develop/notproduct to product to be available (9f07ffd).
> 
> The first is maybe makes the change a bit too hacky in `g1_globals.hpp` (unless there are ways to do that better, i.e. I could move the `GC_G1_EVACUATION_FAILURE_FLAGS` somewhere, or there is a much better preprocessor trick here, so I would like to have you decide.
> 
> Testing: gha, manual checking that in product mode by default no evacuation failure handling is in, but with the flag, and otherwise the same as before, tier1-5
> 
> Thanks,
>   Thomas

Thomas Schatzl has updated the pull request incrementally with one additional commit since the last revision:

  ayang review

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5851/files
  - new: https://git.openjdk.java.net/jdk/pull/5851/files/beaa6c34..c6a94fe8

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5851&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5851&range=00-01

  Stats: 6 lines in 2 files changed: 4 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5851.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5851/head:pull/5851

PR: https://git.openjdk.java.net/jdk/pull/5851