Fix hidden API CTS tests' JNI checks

DexMemberChecker had two issues:
(a) It declared JNI methods finding methods with return type
java.lang.reflect.Method, but these can return Constructor too.
Their common parent is java.lang.reflect.Executable.
(b) It then checked whether the returned method/field is declared
in the expected class by quering `member.getClass()`. That is wrong
and returns the java.lang.reflect.X class object, not the declaring
class. The correct call is `member.getDeclaringClass()`.

Bug: 78574586
Test: (cd cts/tests/signature ; ./runSignatureTests.sh)
Change-Id: I12bad98f29d66e4bb7be981e08e907cdc0ec7e82
1 file changed