RFR: 8314592: Add shortcut to SymbolLookup::find [v7]

[Per Minborg]

> While `SymbolLookup` correctly uses an `Optional` return to denote whether a symbol has been found by the lookup or not (which enables composition of symbol lookups), many clients end up just calling `Optional::get`, or `Optional::orElseThrow()` on the result.
> 
> This PR proposes to add a convenience method `SymbolLookup::findOrThrow` that will do a lookup and, if no symbol can be found, throws an `IllegalArgumentException` with a relevant exception message.

Per Minborg has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 12 additional commits since the last revision:

 - Simplify tests
 - Add a test for null arg
 - Add a test for findOrThrow()
 - Merge branch 'master' into symbol-lookup-findorthrow
 - Change exception type
 - Update src/java.base/share/classes/java/lang/foreign/package-info.java
   
   Co-authored-by: Jorn Vernee <JornVernee at users.noreply.github.com>
 - Update src/java.base/share/classes/java/lang/foreign/SymbolLookup.java
   
   Co-authored-by: Maurizio Cimadamore <54672762+mcimadamore at users.noreply.github.com>
 - Update src/java.base/share/classes/java/lang/foreign/SymbolLookup.java
   
   Co-authored-by: Maurizio Cimadamore <54672762+mcimadamore at users.noreply.github.com>
 - Fix typo
 - Update after PR comments
 - ... and 2 more: https://git.openjdk.org/jdk/compare/76cd531f...0e06e0d6

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/18474/files
  - new: https://git.openjdk.org/jdk/pull/18474/files/e2f6c4c9..0e06e0d6

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18474&range=06
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18474&range=05-06

  Stats: 91042 lines in 1455 files changed: 42444 ins; 38886 del; 9712 mod
  Patch: https://git.openjdk.org/jdk/pull/18474.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18474/head:pull/18474

PR: https://git.openjdk.org/jdk/pull/18474