Fix StdLibTest for platforms with non standard native charset

If native encoding charset is not one of the standard charset, allocate
segment using default charset for printf down call in StdLibTest.

Fixes: eclipse-openj9/openj9#20337

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

test/jdk/java/foreign/StdLibTest.java

@@ -62,6 +62,16 @@ public class StdLibTest extends NativeTestHelper {
 
     final static Charset nativeCharset = Charset.forName(System.getProperty("native.encoding"));
 
+    static MemorySegment allocateSegmentForString(Arena arena, String str) {
+        try {
+            return arena.allocateFrom(str, nativeCharset);
+        } catch (IllegalArgumentException ex) {
+            // Allocate a memory segment using the native encoded bytes
+            byte[] nativeBytes = str.getBytes(nativeCharset);
+            return arena.allocateFrom(ValueLayout.JAVA_BYTE, Arrays.copyOf(nativeBytes, nativeBytes.length + 1));
+        }
+    }
+
     private StdLibHelper stdLibHelper = new StdLibHelper();
 
     @Test(dataProvider = "stringPairs")
@@ -315,7 +325,7 @@ int rand() throws Throwable {
 
         int printf(String format, List<PrintfArg> args) throws Throwable {
             try (var arena = Arena.ofConfined()) {
-                MemorySegment formatStr = arena.allocateFrom(format, nativeCharset);
+                MemorySegment formatStr = allocateSegmentForString(arena, format);
                 return (int)specializedPrintf(args).invokeExact(formatStr,
                         args.stream().map(a -> a.nativeValue(arena)).toArray());
             }
@@ -396,7 +406,7 @@ enum PrintfArg {
         INT(int.class, C_INT, "%d", "%d", arena -> 42, 42),
         LONG(long.class, C_LONG_LONG, "%lld", "%d", arena -> 84L, 84L),
         DOUBLE(double.class, C_DOUBLE, "%.4f", "%.4f", arena -> 1.2345d, 1.2345d),
-        STRING(MemorySegment.class, C_POINTER, "%s", "%s", arena -> arena.allocateFrom("str", nativeCharset), "str");
+        STRING(MemorySegment.class, C_POINTER, "%s", "%s", arena -> allocateSegmentForString(arena, "str"), "str");
 
         final Class<?> carrier;
         final ValueLayout layout;