Add existing HPKE project files

internal/mlkemtest/mlkemtest_go1.26.go

@@ -0,0 +1,16 @@
+//go:build go1.26
+
+package mlkemtest
+
+import (
+	"crypto/mlkem"
+	"crypto/mlkem/mlkemtest"
+)
+
+func Encapsulate768(ek *mlkem.EncapsulationKey768, rand []byte) (sharedKey, ciphertext []byte, err error) {
+	return mlkemtest.Encapsulate768(ek, rand)
+}
+
+func Encapsulate1024(ek *mlkem.EncapsulationKey1024, rand []byte) (sharedKey, ciphertext []byte, err error) {
+	return mlkemtest.Encapsulate1024(ek, rand)
+}