RFR: 8273774: jdk.tools.jlink.internal.Platform::is64Bit() should not hard code for x64 and AARCH64

Wed Sep 15 14:46:12 UTC 2021

Currently, the Platform.is64Bit() hard coded for judging whether the target arch is 64-bit.
The `classes_nocoops.jsa not found` issue can be found while testing CDSPluginTest.java on 64-bit platform, excluding x64 and AARCH64, like mips64.

For solving this issue, we assume that the bits of target UNKNOWN arch is same as the runtime platform.
This patch adds the following lines in the Platform.is64Bit() method.

``` java
if (arch() == Platform.Architecture.UNKNOWN) {
     return (System.getProperty("os.arch").indexOf("64") != -1);
}

Please review this change. Thanks!

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

Commit messages:
 - 8273774: jdk.tools.jlink.internal.Platform::is64Bit() should not hard code for x64 and AARCH64

Changes: https://git.openjdk.java.net/jdk/pull/5519/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5519&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8273774
  Stats: 4 lines in 1 file changed: 4 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5519.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5519/head:pull/5519

PR: https://git.openjdk.java.net/jdk/pull/5519