Run the jni tests using the interpreter.

Run the jni tests using the interpreter.

	* testsuite/libjava.jni/jni.exp (gcj_jni_compile_c_to_so): Append
	options_cxx to shared lib compile command.
	(gcj_jni_test_one): Pass cxxflags to gcj_jni_compile_c_to_so, so
	they are used to link the shared lib, not the main binary.
	Use libjava_invoke to run gij.

From-SVN: r81574