RFR: JDK-8306112 Implementation of JEP 445: Unnamed Classes and Instance Main Methods (Preview) [v31]

[Jim Laskey]

> Add flexible main methods and anonymous main classes to the Java language.

Jim Laskey has updated the pull request incrementally with two additional commits since the last revision:

 - Use getQualifiedName() to indicate unnamed class
 - ClassSymbol#getSimpleName() returning empty name breaks some tools

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Changes:
  - all: https://git.openjdk.org/jdk/pull/13689/files
  - new: https://git.openjdk.org/jdk/pull/13689/files/0edcd9ae..97a522f7

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13689&range=30
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13689&range=29-30

  Stats: 10 lines in 2 files changed: 4 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/13689.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13689/head:pull/13689

PR: https://git.openjdk.org/jdk/pull/13689