RFR: 8296453: Simplify resource_area uses in ClassPathDirEntry::open_stream [v3]

[Xin Liu]

> Currently it is correct, but there are two places we can improve it.
> 
> 1. We should assert that current == Thread::current(). If it were not case, then we would intermix NEW_RESOURCE_ARRAY_IN_THREAD(current, char, path_len) and FREE_RESOURCE_ARRAY(char, path, path_len)!
> 
> 2. We don't need to call FREE_RESOURCE_ARRAY(char, path, path_len) for path in its first exit. It won't release anything because buffer stands in its way.
> 
> The resource area is like this. `Afree(path, path_len)` won't reclaim the space.
> 
> |path | buffer |...|
>                ^hwm

Xin Liu has updated the pull request incrementally with one additional commit since the last revision:

  Update it per reviewer's feedback.

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/11024/files
  - new: https://git.openjdk.org/jdk/pull/11024/files/2de3bc53..d1d925c5

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11024&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11024&range=01-02

  Stats: 5 lines in 1 file changed: 0 ins; 3 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/11024.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11024/head:pull/11024

PR: https://git.openjdk.org/jdk/pull/11024