Fix KotlinReflectPropertyAccessStrategy to yield instead of throwing NPE

[MateuszNaKodach]

WORK IN PROGRESS....

Summary

KotlinReflectPropertyAccessStrategy registers with priority 1000, so PropertyAccessStrategy consults it first for every class. Its propertyFor used kProperty(...)!!, which throws NullPointerException when the target is not a Kotlin class, or when the name does not match exactly one member property.

PropertyAccessStrategy.getProperty walks the registered strategies by priority and moves on when one returns null, which is the documented contract of propertyFor:

while (property == null && strategies.hasNext()) {
    property = strategies.next().propertyFor(targetClass, propertyName);
}

Because this strategy is consulted first, that NPE broke resolution for every consumer instead of letting a lower-priority strategy handle it. propertyFor now returns null in those cases so the chain falls through.

To let the Kotlin override return null, the abstract PropertyAccessStrategy.propertyFor is annotated @Nullable, making the existing "or null if the property could not be found" contract explicit.

Tests

• A non-Kotlin class (RuntimeException) falls through so a lower-priority strategy resolves message.
• An unknown property on a Kotlin class resolves to null.

All extension module tests and the common property tests pass.

[zambrovski]

Nice one

[zambrovski]

Just curious, do we also need one for conversion of Kotlin Types to Java Types? Like Int / Integer, etc...