RFR: 8302514: Misleading error generated when empty class file encountered

[Archie L. Cobbs]

When javac encounters an empty class file, you get the following strange error referring to `java.lang.AutoCloseable`:

Test.java:3: error: cannot access Empty
        new Empty();
            ^
  bad class file: ./Empty.class
    class file contains wrong class: java.lang.AutoCloseable
    Please remove or make sure it appears in the correct subdirectory of the classpath.
1 error

This is a side effect of javac blindly reading past the end of the data in a data buffer. Further investigation revealed three distinct bugs in this area of the code:

1. There are several unchecked corner cases in `ByteBuffer` and `ArrayUtils` that could potentially lead to `ArrayIndexOutOfBoundsException`s and/or infinite loops. Instead we should "fail fast" on any attempt to read or allocate data out of bounds.
1. The method `ByteBuffer.appendStream()` assumes that the result from `InputStream.available()` is always accurate, but this is not guaranteed. As a result, class files could (in theory) be read incorrectly by the compiler, especially when they come from non-standard sources.
1. There is no systematic protection against truncated class files. Instead, depending on where exactly it is truncated, a truncated class file generates one of several possible different errors:
   * `index 25926 is not within pool size 13`
   * `bad constant pool tag: 0 at 28317`
   * `unexpected constant pool tag: 10 at 11`
   * `class file is invalid for class Empty`
   * `class file contains wrong class: java.lang.AutoCloseable`

This patch fixes issues 1 and 2, and addresses 3 by having `ByteBuffer` throw a new unchecked `UnderflowException` if ever data is read past the end of the buffer. Then `PoolReader`, `ClassReader`, and `ModuleNameReader` are updated to catch this exception and convert it into a bad class file error. As a result, truncated class files generate a consistent `class file truncated at offset X` error regardless of where they are truncated.

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

Commit messages:
 - Fix misleading error when empty an class file is encountered.
 - Fix bogus reliance on InputStream.available() in ByteBuffer.appendStream().
 - Tighten up handling of corner cases in ByteBuffer and ArrayUtils.

Changes: https://git.openjdk.org/jdk/pull/12574/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12574&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8302514
  Stats: 353 lines in 10 files changed: 308 ins; 0 del; 45 mod
  Patch: https://git.openjdk.org/jdk/pull/12574.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12574/head:pull/12574

PR: https://git.openjdk.org/jdk/pull/12574