RFR: 8286647: JFR: Build failure when C1 or C2 is disabled after JDK-8282420 [v2]

[Jie Fu]

> Hi all,
> 
> JDK fails to build when c1 or c2 is disabled after JDK-8282420.
> The reason is that c1/c2 code is used without `#ifdef` guards.
> The fix just adds some `#ifdef`.
> 
> Testing:
>  - build   on Linux/x64
>  - jdk/jfr on Linux/x64
> 
> Thanks.
> Best regards,
> Jie

Jie Fu has updated the pull request incrementally with one additional commit since the last revision:

  Revert change in src/hotspot/share/jfr/jfr.hpp

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8680/files
  - new: https://git.openjdk.java.net/jdk/pull/8680/files/99fe830b..50cc937f

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8680&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8680&range=00-01

  Stats: 13 lines in 1 file changed: 1 ins; 11 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8680.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8680/head:pull/8680

PR: https://git.openjdk.java.net/jdk/pull/8680