Replace ReaderWriter::readAllBytes(InputStream) by InputStream::readAllBytes()

The source code of `ReaderWriter::readAllBytes(InputStream)` is a copy of OpenJDK's `InputStream::readAllBytes()` with one sole change needed *solely for one large Oracle customer* (actually a workaround for a bug in a custom `InputStream` of that customer), as explained by @jansupol in the discussion at https://github.com/eclipse-ee4j/jersey/pull/5341#discussion_r1199820780:
```java
if (nread == BUFFER_SIZE) { // This differs from JDK version
break; // prevents a bug (See ReaderWriterTest)
}
```
The mere existence of this method is suboptimal in several directions:
* It stays fixed even if the JRE's method gets fixed, so no bug fixes done in the JRE will be seen in Jersey.
* It stays fixed even if the JRE's method gets enhanced, so no performance optimizations done in the JRE will be seen in Jersey.
* It is custom code based on particularly OpenJDK, so Jersey never sees any performance optimizations already exisiting in *other* JREs.

Besides that, Jersey officially is not an Oracle product anymore, but an Eclipse Foundation open source project, so IMHO it should not contain *any* customer-specific workarounds. Users, even large ones, should fix their bugs instead of further relying on workarounds in open source projects.