RFR: 8338936: StringConcatFactory optimize the construction of MethodType and MethodTypeDesc

[Shaojin Wen]

optimize the construction of MethodType and MethodTypeDesc to reduce memory allocate

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Commit messages:
 - Update src/java.base/share/classes/java/lang/invoke/StringConcatFactory.java
 - Optimize the construction of MethodType and MethodTypeDesc to reduce memory allocate

Changes: https://git.openjdk.org/jdk/pull/20704/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20704&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8338936
  Stats: 34 lines in 1 file changed: 13 ins; 9 del; 12 mod
  Patch: https://git.openjdk.org/jdk/pull/20704.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20704/head:pull/20704

PR: https://git.openjdk.org/jdk/pull/20704