RFR: 8346059: [ASAN] awt_LoadLibrary.c reported compile warning ignoring return value of function by clang17

[SendaoYan]

Hi all,
This PR fix file src/java.desktop/unix/native/libawt/awt/awt_LoadLibrary.c reported compile warning "ignoring return value of function" by clang17, which add check the return value of `realpath` function. Risk is low.

Additional testing:

- [ ]  jtreg tests(include tier1/2/3) on linux-x64 with release build
- [ ]  jtreg tests(include tier1/2/3) on linux-x64 with fastdebug build
- [ ]  jtreg tests(include tier1/2/3) on linux-aarch64 with release build
- [ ]  jtreg tests(include tier1/2/3) on linux-aarch64 with fastdebug build

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Commit messages:
 - 8346059: [ASAN] awt_LoadLibrary.c reported compile warning ignoring return value of function by clang17

Changes: https://git.openjdk.org/jdk/pull/22701/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22701&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8346059
  Stats: 3 lines in 1 file changed: 2 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/22701.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22701/head:pull/22701

PR: https://git.openjdk.org/jdk/pull/22701