RFR: 8338543: ClassBuilder withMethod builders should cache the method type symbol

[Chen Liang]

In #20611 and other investigations, we noted that `MethodTypeDesc.ofDescriptor` is unnecessarily called due to missing caching in ClassBuilder. This patch adds that missing caching functionality.

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Commit messages:
 - 8338543: ClassBuilder withMethod builders should cache the method type symbol

Changes: https://git.openjdk.org/jdk/pull/20627/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20627&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8338543
  Stats: 22 lines in 3 files changed: 18 ins; 3 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/20627.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20627/head:pull/20627

PR: https://git.openjdk.org/jdk/pull/20627