Wrong setter selected in presence of a typed and untyped setter

[jjohannes]

Split out from #2239 (comment)

There is an issue with supporting two setters for the same property with different types (see #1866). We need to fix this:

gradle/subprojects/base-services/src/main/java/org/gradle/internal/reflect/JavaReflectionUtil.java

Lines 123 to 132 in 0b9336f

	public static PropertyMutator writeablePropertyIfExists(Class<?> target, String property) throws NoSuchPropertyException {
	String setterName = toMethodName("set", property);
	for (final Method method : target.getMethods()) {
	if (!method.getName().equals(setterName) || PropertyAccessorType.of(method) != PropertyAccessorType.SETTER) {
	continue;
	}
	return new MethodBackedPropertyMutator(property, method);
	}
	return null;
	}

At the moment it depends on the order in which methods are iterated if we grep the right one. That explains why it is difficult to reproduce.

Here is a test that fails sometimes, but not always:

def "can always change buildDir in properties file"() {
    when:
    file('gradle.properties') << """
        buildDir=otherBuild
    """
    then:
    succeeds ':help'
}