RFR: 8356308: Assert with -Xlog:class+path when classpath has an empty element [v3]

[Ioi Lam]

> When the classpath has an element that's the empty string (e.g., `java  -Xlog:class+path -cp :abc ...`, where the first element is `""` and the second element is `"abc"`), the VM asserts.
> 
> The fix is simple:
> 
> 
> -     if (do_substitute) {
> +     if (do_substitute && remove_prefix_len > 0) {
> 
> 
> I also improved the logs to help debugging classpath mismatches when using the AOT cache.

Ioi Lam has updated the pull request incrementally with one additional commit since the last revision:

  @dholmes-ora comments

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/25372/files
  - new: https://git.openjdk.org/jdk/pull/25372/files/400b93c9..21e9a39c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25372&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25372&range=01-02

  Stats: 3 lines in 2 files changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/25372.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25372/head:pull/25372

PR: https://git.openjdk.org/jdk/pull/25372