SpEL's Indexer.setArrayElement() incorrectly requests conversion to wrapper instead of primitive

[sbrannen]

The setArrayElement(...) method in SpEL's Indexer incorrectly requests conversion to wrappers instead of primitives when setting an element in a primitive array.

See the associated disabled test:

spring-framework/spring-expression/src/test/java/org/springframework/expression/spel/SetValueTests.java

Lines 167 to 182 in 2e56361

	@Disabled("Disabled due to bug in Indexer.setArrayElement() regarding primitive/wrapper types")
	@Test
	void setArrayElementToPrimitiveFromEmptyCollectionFails() {
	List<Object> emptyList = List.of();
	// TODO These fail because CollectionToObjectConverter returns null.
	// It currently throws: java.lang.IllegalStateException: Null conversion result for index [[]].
	// Whereas, it should throw a SpelEvaluationException.
	setValueAndExpectError("arrayContainer.booleans[1]", emptyList);
	setValueAndExpectError("arrayContainer.chars[1]", emptyList);
	setValueAndExpectError("arrayContainer.shorts[1]", emptyList);
	setValueAndExpectError("arrayContainer.bytes[1]", emptyList);
	setValueAndExpectError("arrayContainer.ints[1]", emptyList);
	setValueAndExpectError("arrayContainer.longs[1]", emptyList);
	setValueAndExpectError("arrayContainer.floats[1]", emptyList);
	setValueAndExpectError("arrayContainer.doubles[1]", emptyList);
	}