RFR: 8187655: jdk.lambda.vm.InterfaceAccessFlagsTest.testPrivateMethodCall needs update after nestmates support

[Mandy Chung]

`jdk.lambda.vm.InterfaceAccessFlagsTest` uses `ClassToInterfaceConverter` to mechanically convert a classfile for a Class into an in-memory class representation of an equivalent Interface.  `testPrivateMethodCall`  tests to invoke a private method. Before nestmates, invoking a private class method and a private interface method both use `Invokespecial`.   With the nestmate changes, the class uses `invokevirtual` but the interface must use `invokeinterface` but this conversion is not handled by the existing `ClassToInterfaceConverter`.

This fix converts `ClassToInterfaceConverter` to use the Class-File API to properly convert a classfile from a class to an interface including method invocation from `invokevirtual` to `invokeinterface`.  The old custom bytecode manipulation code can be dropped.

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Commit messages:
 - 8187655: InterfaceAccessFlagsTest.testPrivateMethodCall needs update after nestmates support

Changes: https://git.openjdk.org/jdk/pull/16526/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16526&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8187655
  Stats: 594 lines in 5 files changed: 5 ins; 538 del; 51 mod
  Patch: https://git.openjdk.org/jdk/pull/16526.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16526/head:pull/16526

PR: https://git.openjdk.org/jdk/pull/16526