RFR: 8322636: [JVMCI] HotSpotSpeculationLog can be inconsistent across a single compile [v2]

[David Leopoldseder]

> This PR fixes a subtle inconsistency in `HotSpotSpeculationLog` .
> 
> Normal uses of `HotSpotSpeculationLog` work by using a `SpeculationReason` and asking the speculation log via `maySpeculate` if the speculation can be performed, i.e., if it failed before for the given method.  An example for this can be seen in Graal https://github.com/oracle/graal/blob/master/compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/nodes/loop/CountedLoopInfo.java#L591C15-L591C15 
> The implicit assumption is that the speculation log, `HotSpotSpeculationLog` in particular collects failed speculations at the beginning of a compile and then stays consistent during the compile. Why is that? - Because if there are new failed speculations added to the failed speculations during the compile - the compiler would speculate again on those in an inconsistent way. E.g. at the beginning of a compile a certain speculation has not failed yet and the compiler thinks it can do optimization xyz using a speculation  - later during the compilation process it consults the speculation log but gets a different answer. All those inconsistent speculations that already failed will anyway later fail code installation in jvmci (they will throw a bailout during `HotSpotCodeCacheProvider#installCode` https://github.com/openjdk/jdk/blob/master/src/jdk.internal.vm.ci/share/classes/jdk/vm/ci/hotspot/HotSpotSpeculationLog.java#L192 ). Thus, we should at least return a consistent result during
  a compile.
> The problem for consistency here, that also makes troubles on the graal side, is that `maySpeculate` itself can collect failed speculations if there have not been any previously, i.e., `failedSpeculations == null`.
> In order to make the speculation log consistent across an entire JVMCI compile this PR removes the collection of failed speculations in `maySpeculate`.

David Leopoldseder has updated the pull request incrementally with one additional commit since the last revision:

  8322636: [JVMCI] HotSpotSpeculationLog add javadoc to maySpeculate

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/17183/files
  - new: https://git.openjdk.org/jdk/pull/17183/files/810e42ad..ef026267

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17183&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17183&range=00-01

  Stats: 6 lines in 1 file changed: 6 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/17183.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17183/head:pull/17183

PR: https://git.openjdk.org/jdk/pull/17183