RFR: 8200145: Conditional expression mistakenly treated as standalone

[Guoxiong Li]

Hi all,

If the argument `Type t` of the method `Types.unboxedType` is an `ErrorType`, the `Types.unboxedType` may return the wrong result. And in this case, `Attr.isBooleanOrNumeric` and `Attr.isBooleanOrNumeric` return the wrong result, too.

This patch fixes it and adds a test case.
Thank you for taking the time to review.

Best Regards.
-- xiong

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Commit messages:
 - 8200145: Conditional expression mistakenly treated as standalone

Changes: https://git.openjdk.java.net/jdk/pull/2324/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2324&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8200145
  Stats: 46 lines in 3 files changed: 45 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2324.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2324/head:pull/2324

PR: https://git.openjdk.java.net/jdk/pull/2324