RFR: 8315970: Big-endian issues after JDK-8310929

[温绍锦]

https://bugs.openjdk.org/browse/JDK-8310929

@TheRealMDoerr Feedback:


We're getting test failures on AIX:
compiler/intrinsics/Test8215792.java
compiler/intrinsics/string/TestStringIntrinsics.java
runtime/CompactStrings/TestMethodNames.java
runtime/StringIntrinsic/StringIndexOfChar.java
Is there a problem with Big Endian?

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Commit messages:
 - fix PR #14699 big endian error

Changes: https://git.openjdk.org/jdk/pull/15652/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15652&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8315970
  Stats: 42 lines in 1 file changed: 18 ins; 16 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/15652.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15652/head:pull/15652

PR: https://git.openjdk.org/jdk/pull/15652