Clean up some uses of String::substr

Cases where the end position is either equvalent to the default or past
the end of the string.

platform/android/java_class_wrapper.cpp

@@ -924,7 +924,7 @@ bool JavaClassWrapper::_get_type_sig(JNIEnv *env, jobject obj, uint32_t &sig, St
 	if (str_type.begins_with("[")) {
 		t = JavaClass::ARG_ARRAY_BIT;
 		strsig = "[";
-		str_type = str_type.substr(1, str_type.length() - 1);
+		str_type = str_type.substr(1);
 		if (str_type.begins_with("[")) {
 			print_line("Nested arrays not supported for type: " + str_type);
 			return false;