RFR: 8286562: GCC 12 reports some compiler warnings [v9]

[Yasumasa Suenaga]

> I saw some compiler warnings when I tried to build OpenJDK with GCC 12.0.1 on Fedora 36.
> As you can see, the warnings spreads several areas. Let me know if I should separate them by area.
> 
> * -Wstringop-overflow
>     * src/hotspot/share/oops/array.hpp
>     * src/hotspot/share/jfr/recorder/checkpoint/types/traceid/jfrTraceIdBits.inline.hpp
> 
> In member function 'void Array<T>::at_put(int, const T&) [with T = unsigned char]',
>     inlined from 'void ConstantPool::tag_at_put(int, jbyte)' at /home/ysuenaga/github-forked/jdk/src/hotspot/share/oops/constantPool.hpp:126:64,
>     inlined from 'void ConstantPool::method_at_put(int, int, int)' at /home/ysuenaga/github-forked/jdk/src/hotspot/share/oops/constantPool.hpp:380:15,
>     inlined from 'ConstantPool* BytecodeConstantPool::create_constant_pool(JavaThread*) const' at /home/ysuenaga/github-forked/jdk/src/hotspot/share/classfile/bytecodeAssembler.cpp:85:26:

Yasumasa Suenaga has updated the pull request incrementally with two additional commits since the last revision:

 - Change Array::data() implementation
 - Avoid stringop-overflow warning in jfrTraceIdBits.inline.hpp

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8646/files
  - new: https://git.openjdk.java.net/jdk/pull/8646/files/042c1c70..17cda224

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8646&range=08
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8646&range=07-08

  Stats: 39 lines in 4 files changed: 18 ins; 18 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8646.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8646/head:pull/8646

PR: https://git.openjdk.java.net/jdk/pull/8646