Fix bugs in the JavaHL environment wrapper.

* subversion/bindings/javahl/native/jniwrapper/jni_env.hpp
  (Env::DeleteGlobalRef, Env::PopLocalFrame, Env::IsInstanceOf):
   Declare as non-throwing.
  (Env::GetStringUTFChars, Env::NewObjectArray, Env::Get*ArrayElements):
   Throw an OutOfMemoryError instead of an std::runtime_exception
   if the function fails.
  (Env::ReleaseStringUTFChars, Env::NewObjectArray,
   Env::New*Array, Env::Release*ArrayElements):
   Do not check for Java exceptions.
  (Env::Get*ArrayElements, Env::Release*ArrayElements): Check for null array.
  (Env::GetArrayLength): A null array yields zero length, not negative.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1544092 13f79535-47bb-0310-9956-ffa450edef68