Fix hasOwnProperty on NativeJavaObject

[Schmidor]

This failed since #1157 with "TypeError: Expected argument of type
object, but instead had type object"

org.mozilla.javascript.EcmaError: TypeError: Expected argument of type object, but instead had type object (#1)
	at org.mozilla.javascript.ScriptRuntime.constructError(ScriptRuntime.java:4568)
	at org.mozilla.javascript.ScriptRuntime.constructError(ScriptRuntime.java:4549)
	at org.mozilla.javascript.ScriptRuntime.typeError(ScriptRuntime.java:4581)
	at org.mozilla.javascript.ScriptRuntime.typeErrorById(ScriptRuntime.java:4586)
	at org.mozilla.javascript.ScriptableObject.ensureScriptableObject(ScriptableObject.java:1845)
	at org.mozilla.javascript.AbstractEcmaObjectOperations.hasOwnProperty(AbstractEcmaObjectOperations.java:37)
	at org.mozilla.javascript.NativeObject.execIdCall(NativeObject.java:216)
	at org.mozilla.javascript.IdFunctionObject.call(IdFunctionObject.java:84)
	at org.mozilla.javascript.ScriptRuntime.applyOrCall(ScriptRuntime.java:2769)
	at org.mozilla.javascript.BaseFunction.execIdCall(BaseFunction.java:327)
	at org.mozilla.javascript.IdFunctionObject.call(IdFunctionObject.java:84)
	at org.mozilla.javascript.optimizer.OptRuntime.call2(OptRuntime.java:46)
	at org.mozilla.javascript.gen.c_1._c_script_0(:1)
	at org.mozilla.javascript.gen.c_1.call()
	at org.mozilla.javascript.ContextFactory.doTopCall(ContextFactory.java:383)
	at org.mozilla.javascript.ScriptRuntime.doTopCall(ScriptRuntime.java:3871)
	at org.mozilla.javascript.gen.c_1.call()
	at org.mozilla.javascript.gen.c_1.exec()
	at org.mozilla.javascript.Context.evaluateString(Context.java:1170)
	at org.mozilla.javascript.tests.NativeObjectTest.testNativeJavaObject_hasOwnProperty(NativeObjectTest.java:100)

[p-bakker]

LGTM

[gbrail]

This looks good -- thanks for finding, fixing, and writing a test!