Allow internal JDK builds to be used with Substrate. (#1202)

When building the JDK from sources, by default the version name will contain the "internal-" String.
This patch allows JDK versions containing this "internal-" String to be used as sources for GraalVM builds

Fix for #1201

src/main/java/com/gluonhq/substrate/model/InternalProjectConfiguration.java

@@ -657,7 +657,8 @@ public Version getGraalVMJavaVersion() throws IOException {
         if (responses == null || responses.isEmpty()) {
             throw new IOException("Couldn't determine GraalVM's Java version");
         }
-        Matcher m = r.matcher(responses.get(0));
+        String realVersion = responses.get(0).replaceAll("-internal", "");
+        Matcher m = r.matcher(realVersion);
         if (!m.find()) {
             throw new IOException("Couldn't determine GraalVM's Java version for " + responses.get(0));
         }