[lworld] RFR: 8235914: [lworld] Profile acmp bytecode [v5]

[Roland Westrelin]

> This includes:
> - a new ProfileData structure to profile both inputs to acmp
> - profile collection at acmp in the interpreter on x86
> - profile collection at acmp in c1 generated code on x86
> - changes to c2's acmp implementation to leverage profiling (both existing profiling through type speculation and new
>   profile data at acmp)
> - small tweaks to the assembly code generated for acmp
> - a change to the implementation of LIRGenerator::profile_null_free_array() so it doesn't use a branch (which is
>   dangerous given the register allocator is not aware of branches added at the LIR level)
> - new tests
> 
> Profile collection happens unconditionally. Leveraging profiling at acmp is under UseACmpProfile which is false by
> default.

Roland Westrelin has refreshed the contents of this pull request, and previous commits have been removed. The
incremental views will show differences compared to the previous content of the PR. The pull request contains one new
commit since the last revision:

  review

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Changes:
  - all: https://git.openjdk.java.net/valhalla/pull/185/files
  - new: https://git.openjdk.java.net/valhalla/pull/185/files/b88029c6..60561b7d

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=valhalla&pr=185&range=04
 - incr: https://webrevs.openjdk.java.net/?repo=valhalla&pr=185&range=03-04

  Stats: 6 lines in 1 file changed: 0 ins; 0 del; 6 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/185.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/185/head:pull/185

PR: https://git.openjdk.java.net/valhalla/pull/185