RFR: 8258662: JDK 17ea: Crash compiling instanceof check involving sealed interface [v2]

[Guoxiong Li]

> Hi all,
> 
> The method `Types.isCastable` uses method `Types.areDisjoint` to do some check. But `Types.isCastable` doesn't check the type of the parameter before invoking method `Types.areDisjoint`. This patch adds the corresponding check and add a test case.
> 
> Thank you for taking the time to review.
> 
> Best Regards.

Guoxiong Li has updated the pull request incrementally with one additional commit since the last revision:

  Use methods instead of instanceof

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1849/files
  - new: https://git.openjdk.java.net/jdk/pull/1849/files/41e94f2c..3b77d032

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1849&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1849&range=00-01

  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1849.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1849/head:pull/1849

PR: https://git.openjdk.java.net/jdk/pull/1849