RFR: 8343167: Unnecessary define checks in InterpreterRuntime after JDK-8199809

[Aleksey Shipilev]

[JDK-8199809](https://bugs.openjdk.org/browse/JDK-8199809) left a few unnecessary things in InterpreterRuntime::SignatureHandlerGenerator::SignatureHandlerGenerator. In `interpreterRT_x86_64.cpp`: no need for `AMD64` checks. In `interpreterRT_x86_32.cpp`: no need for `AMD64` and `WIN64` checks. 

Additional testing:
 - [x] Linux x86_64 server fastdebug, `make bootcycle-images`
 - [x] Linux x86_32 server fastdebug, `make bootcycle-images`
 - [ ] GHA

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Commit messages:
 - Fix

Changes: https://git.openjdk.org/jdk/pull/21747/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21747&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8343167
  Stats: 12 lines in 2 files changed: 0 ins; 12 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/21747.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21747/head:pull/21747

PR: https://git.openjdk.org/jdk/pull/21747