RFR: 8310454: Introduce static-libs-graal bundle

[Erik Joelsson]

[JDK-8307858](https://bugs.openjdk.org/browse/JDK-8307858) added libjvm.a to the set of static-libs in the static-libs image and subsequently the static-libs bundle. The main user of the existing static-image was the graal build, which doesn't need libjvm. Since libjvm is considerably bigger than all the other libraries, a static-libs-graal-image was introduced to cover the graal build usecase. There was no corresponding bundles target added however, so for graal builds depending on stored/published bundles, there is no way of skipping out of libjvm.

To fix this, this patch introduces a new make target: `static-libs-graal-bundles`.

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Commit messages:
 - JDK-8310454

Changes: https://git.openjdk.org/jdk/pull/15406/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15406&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8310454
  Stats: 30 lines in 3 files changed: 29 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/15406.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15406/head:pull/15406

PR: https://git.openjdk.org/jdk/pull/15406