Use native encoded bytes when making a downcall to standard printf

When making a downcall to standard printf function, use native encoded
bytes as argument instead of UTF-8 bytes.

Signed-off-by: Rahil Shah <[email protected]>

Author: r30shah

test/jdk/java/foreign/StdLibTest.java

@@ -21,6 +21,12 @@
  * questions.
  */
 
+/*
+ * ===========================================================================
+ * (c) Copyright IBM Corp. 2024, 2024 All Rights Reserved
+ * ===========================================================================
+ */
+
 /*
  * @test
  * @run testng/othervm --enable-native-access=ALL-UNNAMED StdLibTest
@@ -305,8 +311,10 @@ int rand() throws Throwable {
         }
 
         int printf(String format, List<PrintfArg> args) throws Throwable {
+            byte[] nativeEncodingBytes = format.getBytes(System.getProperty("native.encoding"));
+            nativeEncodingBytes = Arrays.copyOf(nativeEncodingBytes, nativeEncodingBytes.length + 1);
             try (var arena = Arena.ofConfined()) {
-                MemorySegment formatStr = arena.allocateFrom(format);
+                MemorySegment formatStr = arena.allocateArray(ValueLayout.JAVA_BYTE, nativeEncodingBytes);
                 return (int)specializedPrintf(args).invokeExact(formatStr,
                         args.stream().map(a -> a.nativeValue(arena)).toArray());
             }