IJPL-159869 Improve performance of decodeUsingGraphicalState

Create the char array only once.
Previously, we created the array in StringBuilder and also had to expand it on overflow.
Also, we created an array inside `StringBuilder.toString()` and then in `String.toCharArray()`.

core/src/com/jediterm/terminal/model/JediTerminal.java

@@ -167,12 +167,11 @@ public void writeDoubleByte(final char[] bytesOfChar) throws UnsupportedEncoding
 
 
   private char[] decodeUsingGraphicalState(String string) {
-    StringBuilder result = new StringBuilder();
-    for (char c : string.toCharArray()) {
-      result.append(myGraphicSetState.map(c));
+    char[] chars = string.toCharArray();
+    for (int i = 0; i < chars.length; i++) {
+      chars[i] = myGraphicSetState.map(chars[i]);
     }
-
-    return result.toString().toCharArray();
+    return chars;
   }
 
   public void writeUnwrappedString(String string) {