RFR: 7902795: Provide a "release" file for AsmTools builds

[Leonid Kuskov]

This is the fix for https://bugs.openjdk.java.net/browse/CODETOOLS-7902795
The fix provides a generation of a "release" file in the product image.
The release file contains the following:
SOURCE="git:f00d0a27fa21e834dc2543292a2d55215bcbf426"
VERSION="7.0_10"
VERSION_DATE="January 14, 2021"
MILESTONE="ea"

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Commit messages:
 - 7902795: Provide a release file for AsmTools builds
 - Merge remote-tracking branch 'upstream/master'
 - 7902800: jasm incorrectly calculates ldc index in certain cases
 - 7902688: Asmtools support for JEP 360: changing the name from SealedTypes to SealedClasses
 - 7902686: Jasm incorrectly sets up the SourceFile attribute on Windows platform
 - 7902681: Asmtools build fails if Default Java File Encoding is set to ASCII
 - Merge branch 'CODETOOLS-7902659'
 - 7902659: Correct unconditional call of System.exit in printVersion (Main.java)
 - Merge branch 'CODETOOLS-7902660'
 - 7902660: jdis includes unnecessary Field references in MethodHandle parameters while printing static params of a bsm and skips the method tag in ldc# instructions

Changes: https://git.openjdk.java.net/asmtools/pull/14/files
 Webrev: https://webrevs.openjdk.java.net/?repo=asmtools&pr=14&range=00
  Issue: https://bugs.openjdk.java.net/browse/CODETOOLS-7902795
  Stats: 47 lines in 2 files changed: 26 ins; 10 del; 11 mod
  Patch: https://git.openjdk.java.net/asmtools/pull/14.diff
  Fetch: git fetch https://git.openjdk.java.net/asmtools pull/14/head:pull/14

PR: https://git.openjdk.java.net/asmtools/pull/14