[jdk17u-dev] RFR: 8312489: Increase jdk.jar.maxSignatureFileSize default which is too low for JARs such as WhiteSource/Mend unified agent jar

[Andrew John Hughes]

The security fix, JDK-8300596, introduced a maximum size for signature-related files in JAR files, via the `jdk.jar.maxSignatureFileSize` property. The default value of 8MB has since proven to be too low for some JARs in general use. This change doubles it to 16MB, while still being much lower than the previous `MAX_ARRAY_SIZE` value of `Integer.MAX_VALUE - 8`

This pull request contains a clean backport of commit [e47a84f2](https://github.com/openjdk/jdk/commit/e47a84f23dd2608c6f5748093eefe301fb5bf750) from the [openjdk/jdk](https://git.openjdk.org/jdk) repository.

The commit being backported was authored by Hai-May Chao on 31 Jul 2023 and was reviewed by Sean Mullan and Matthias Baesken.

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Commit messages:
 - Backport e47a84f23dd2608c6f5748093eefe301fb5bf750

Changes: https://git.openjdk.org/jdk17u-dev/pull/1703/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1703&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8312489
  Stats: 9 lines in 2 files changed: 2 ins; 0 del; 7 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1703.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1703/head:pull/1703

PR: https://git.openjdk.org/jdk17u-dev/pull/1703