Don't create JNINativeCallWrapperMethods for JNICallTrampolineMethods

`JNICallTrampolineMethod`s can not be invoked from Java, so creating
`JNINativeCallWrapperMethod`s for them is not needed.

Closes: oracle#4018

substratevm/src/com.oracle.svm.jni/src/com/oracle/svm/jni/hosted/JNINativeCallWrapperSubstitutionProcessor.java

@@ -41,6 +41,9 @@ class JNINativeCallWrapperSubstitutionProcessor extends SubstitutionProcessor {
     @Override
     public ResolvedJavaMethod lookup(ResolvedJavaMethod method) {
         assert method.isNative() : "Must have been registered as a native substitution processor";
+        if (method instanceof JNICallTrampolineMethod) {
+            return method;
+        }
         return callWrappers.computeIfAbsent(method, JNINativeCallWrapperMethod::new);
     }