Convert primitive array to Object[] when invoking varargs method in SpEL

Prior to this commit, SpEL incorrectly wrapped a primitive array in an
Object[] array when invoking Object[] varargs methods and constructors.

This commit addresses this by updating the convertArguments(...) method
in ReflectionHelper as follows when the user supplies the varargs
already packaged in a primitive array.

- When deciding whether to convert a single element passed as varargs,
  we now check if the argument is an array that is assignable to the
  varargs array type.

- When converting an array supplied as the varargs, we convert that
  array to the varargs array type.

Closes gh-33317

spring-expression/src/test/java/org/springframework/expression/spel/MethodInvocationTests.java

@@ -23,7 +23,6 @@ import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.List;
 
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.expression.Expression;
@@ -357,7 +356,6 @@ class MethodInvocationTests extends AbstractExpressionTests {
 		evaluate("formatPrimitiveVarargs('x -> %s %s', '2', 3.0d)", "x -> 2 3", String.class);
 	}
 
-	@Disabled("Primitive array to Object[] conversion is not currently supported")
 	@Test
 	void testVarargsWithPrimitiveArrayToObjectArrayConversion() {
 		evaluate("formatObjectVarargs('x -> %s %s %s', new short[]{1, 2, 3})", "x -> 1 2 3", String.class); // short[] to Object[]

spring-expression/src/test/java/org/springframework/expression/spel/VariableAndFunctionTests.java

@@ -16,7 +16,6 @@
 
 package org.springframework.expression.spel;
 
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.expression.spel.standard.SpelExpressionParser;
@@ -199,7 +198,6 @@ class VariableAndFunctionTests extends AbstractExpressionTests {
 		evaluate("#formatPrimitiveVarargs('x -> %s %s %s', new String[]{'1', '2', '3'})", "x -> 1 2 3", String.class); // String[] to int[]
 	}
 
-	@Disabled("Primitive array to Object[] conversion is not currently supported")
 	@Test
 	void functionFromMethodWithVarargsAndPrimitiveArrayToObjectArrayConversion() {
 		evaluate("#varargsObjectFunction(new short[]{1, 2, 3})", "[1, 2, 3]", String.class); // short[] to Object[]