RFR: 8272564: Incorrect attribution of method invocations of Object methods on interfaces

[Jan Lahoda]

Consider these declarations:

    interface I {
        public String toString();
    }
    interface J extends I {}


There are two issues with the `toString` inherited from `I` into `J`:
-`Trees.isAccessible(..., I.toString, J)` will return false, because `Resolve.isAccessible` will return false, because `Resolve.notOverriddenIn` returns false, because the `Object.toString` method is found as an implementation of `I.toString` in the context of `J`. This is unfortunate, because `Elements.getAllMembers(J)` will return `I.toString` as a member, not `Object.toString`, so any API client listing all members and then validating them using `Trees.isAccessible` will filter `toString` out. The proposed solution is to avoid using the methods from `java.lang.Object` as implementations of interface methods in `Resolve.notOverriddenIn`. (Interfaces don't inherit from `j.l.Object` per my understanding of JLS.)
-as a slightly less problematic case, consider:

I i = null;
i.toString(); //AST and classfile contain call to I.toString()
J j = null;
j.toString(); //AST and classfile contain call to j.l.Object.toString()


I believe the second invocation should also preferably be a call to `I.toString()`, not a call to `j.l.Object.toString()`. The reason for this behavior is that in javac, interfaces have `j.l.Object` as a supertype, so method lookups over interfaces will look into `j.l.Object` before looking into the superinterfaces, and the concrete method will prevail over the super interface method found later. The proposal is, for interfaces, to only look into `j.l.Object` is a method is not found in the interface and its superinterfaces.

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Commit messages:
 - 8272564: Incorrect attribution of method invocations of Object methods on interfaces

Changes: https://git.openjdk.java.net/jdk/pull/5165/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5165&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8272564
  Stats: 169 lines in 5 files changed: 166 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5165.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5165/head:pull/5165

PR: https://git.openjdk.java.net/jdk/pull/5165