RFR: 8365060: Historical data for JDK 8 should include the jdk.net package

[Jan Lahoda]

In JDK 8, the package `jdk.net` was exported and part of `rt.jar`, and hence should have been part of the historical data for `--release`, but it is not. The primary goal of this PR is to add historical data for `jdk.net` for JDK 8.

The changes herein are based on JDK 8u462. I used the Probe running on JDK 8 to dump the classfiles, along these lines:

$ java -classpath .../make/langtools/src/classes/ build.tools.symbolgenerator.Probe /tmp/jdk8-classfiles


and then the up-to-date `CreateSymbols` to generate the `sym.txt` files, along these lines:

java --add-exports jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED --add-exports jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED  CreateSymbols.java build-description-incremental-file .../src/jdk.compiler/share/data/symbols/symbols .../src/jdk.compiler/share/data/symbols/include.list 8 /tmp/jdk8-classfiles '<none>' --normalize-method-flags


There are a few APIs that have been added for this release, and a few representational changes.

Most notably - the ordering of "removal" entries (i.e. those that start with `-`) and "add" entries is much more strict in the current `CreateSymbols`, and so there are some changes where the removal entries are moved to the front. I went through those, and they seem OK to me.

I'll add specific comments to the other updates to the files.

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Commit messages:
 - Merge branch 'master' into JDK-8365060
 - Fixing test.
 - 8365060: Historical data for JDK 8 should include the jdk.net package

Changes: https://git.openjdk.org/jdk/pull/26817/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26817&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8365060
  Stats: 289 lines in 13 files changed: 205 ins; 67 del; 17 mod
  Patch: https://git.openjdk.org/jdk/pull/26817.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26817/head:pull/26817

PR: https://git.openjdk.org/jdk/pull/26817