RFR: JDK-8253700: spurious "extends Throwable" at end of Optional.orElseThrow method declaration

Tue Sep 29 23:53:41 UTC 2020

The link for the `throws` type was not filtering out the bounds. A new `LinkInfoImpl.Kind` is added for `THROWS_TYPE`.

The loop to generate the list of exceptions is simplified.

A new test is provided. The generated API for `Optional.orElseThrow` has also been verified as correct.

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Commit messages:
 - JDK-8253700: spurious "extends Throwable" at end of Optional.orElseThrow method declaration

Changes: https://git.openjdk.java.net/jdk/pull/417/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=417&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8253700
  Stats: 118 lines in 3 files changed: 101 ins; 7 del; 10 mod
  Patch: https://git.openjdk.java.net/jdk/pull/417.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/417/head:pull/417

PR: https://git.openjdk.java.net/jdk/pull/417