[jdk16] 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.
> 
> The original patch is in https://github.com/openjdk/jdk/pull/1849.
> 
> 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:

  Modify legal header.

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Changes:
  - all: https://git.openjdk.java.net/jdk16/pull/63/files
  - new: https://git.openjdk.java.net/jdk16/pull/63/files/4b07c7bc..1dec0e3c

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk16&pr=63&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk16&pr=63&range=00-01

  Stats: 3 lines in 1 file changed: 0 ins; 2 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk16/pull/63.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk16 pull/63/head:pull/63

PR: https://git.openjdk.java.net/jdk16/pull/63