Allow existence of overlapping getter, is-getter

[cowtowncoder]

(see FasterXML/jackson-core#79 as background)

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After thinking this through, I think I agree with the idea that following case should be legal:

public class Value {
   public boolean isValue();
   public String getValue();

}

even though it could theoretically be problematic. And we probably do not even need configurable feature, unless we find real cases where exception would have been better alternative than simply using 'getValue()'.

EDIT (29-Apr-2022): Just to make it explicit, in above case method getValue() would be selected as THE getter to use (and isValue() ignored).