Merge java.nio.charset from jdk-11.0.13-ga into the aosp/master branch

List of files:
  ojluni/src/main/java/java/nio/charset/Charset.java
  ojluni/src/main/java/java/nio/charset/StandardCharsets.java
  ojluni/src/test/java/nio/charset/Charset/Contains.java
  ojluni/src/test/java/nio/charset/Charset/Default.java
  ojluni/src/test/java/nio/charset/Charset/EmptyCharsetName.java
  ojluni/src/test/java/nio/charset/Charset/EncDec.java
  ojluni/src/test/java/nio/charset/Charset/IllegalCharsetName.java
  ojluni/src/test/java/nio/charset/Charset/NullCharsetName.java

Bug: 259687960
Test: N/A
Change-Id: I117d6990e89142bb058e60de48bc2e4694a95d7b