Remove null check before calling initCause

Author: GoeLin

src/java.base/share/classes/com/sun/crypto/provider/DHPrivateKey.java

@@ -373,9 +373,7 @@ private void readObject(ObjectInputStream stream)
             c = decode(encodedKeyIntern);
         } catch (IOException e) {
             InvalidObjectException ioe = new InvalidObjectException("Invalid encoding");
-            if (ioe != null) {
-                ioe.initCause(e);
-            }
+            ioe.initCause(e);
             throw ioe;
         }
         if (!Arrays.equals(c.key, key) || !c.x.equals(x) || !c.p.equals(p)

src/java.base/share/classes/com/sun/crypto/provider/DHPublicKey.java

@@ -380,9 +380,7 @@ private void readObject(ObjectInputStream stream)
             c = decode(encodedKeyIntern);
         } catch (IOException e) {
             InvalidObjectException ioe = new InvalidObjectException("Invalid encoding");
-            if (ioe != null) {
-                ioe.initCause(e);
-            }
+            ioe.initCause(e);
             throw ioe;
         }
         if (!Arrays.equals(c.key, key) || !c.y.equals(y) || !c.p.equals(p)