RFR: 8265061: Simplify MethodHandleNatives::canBeCalledVirtual

[Claes Redestad]

Desugaring the single-case switch in MethodHandleNatives::canBeCalledVirtual is a cleanup and minimal startup improvement on apps spinning up MethodHandles.

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Commit messages:
 - Remove switch in canBeCalledVirtual

Changes: https://git.openjdk.java.net/jdk/pull/3433/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3433&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8265061
  Stats: 5 lines in 1 file changed: 0 ins; 3 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3433.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3433/head:pull/3433

PR: https://git.openjdk.java.net/jdk/pull/3433