Names ProblemReporter.validateX

Every once in a while I get confused seeing code like
```java
if (problemReporter().validateJavaFeatureSupport(..)) {
...
}
```

In my book "validate" relates to "valid", so if it answers true I expect the thing to be valid.

I'm sure whoever came up with this terminology (@jarthana ?) has his own way to read this, so I don't want to unilaterally override this, and simply inverting the logic while keeping the name only adds to the confusion. But perhaps we can come up with a name pattern that speaks to all of us?

Cc: @mpalat @srikanth-sankaran