add and registor Python file type detector, so that the polyglot launcher works

(cherry picked from commit 316b4a7)

Author: timfel

graalpython/com.oracle.graal.python/src/META-INF/services/java.nio.file.spi.FileTypeDetector

@@ -0,0 +1 @@
+com.oracle.graal.python.PythonFileDetector

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/PythonFileDetector.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2017, 2018, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * The Universal Permissive License (UPL), Version 1.0
+ *
+ * Subject to the condition set forth below, permission is hereby granted to any
+ * person obtaining a copy of this software, associated documentation and/or
+ * data (collectively the "Software"), free of charge and under any and all
+ * copyright rights in the Software, and any and all patent rights owned or
+ * freely licensable by each licensor hereunder covering either (i) the
+ * unmodified Software as contributed to or provided by such licensor, or (ii)
+ * the Larger Works (as defined below), to deal in both
+ *
+ * (a) the Software, and
+ *
+ * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
+ * one is included with the Software each a "Larger Work" to which the Software
+ * is contributed by such licensors),
+ *
+ * without restriction, including without limitation the rights to copy, create
+ * derivative works of, display, perform, and distribute the Software and make,
+ * use, sell, offer for sale, import, export, have made, and have sold the
+ * Software and the Larger Work(s), and to sublicense the foregoing rights on
+ * either these or other terms.
+ *
+ * This license is subject to the following condition:
+ *
+ * The above copyright notice and either this complete permission notice or at a
+ * minimum a reference to the UPL must be included in all copies or substantial
+ * portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.oracle.graal.python;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.nio.file.spi.FileTypeDetector;
+
+public final class PythonFileDetector extends FileTypeDetector {
+    @Override
+    public String probeContentType(Path path) throws IOException {
+        if (path.getFileName().toString().endsWith(".py")) {
+            return PythonLanguage.MIME_TYPE;
+        }
+        return null;
+    }
+}

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/PythonLanguage.java

@@ -73,15 +73,14 @@
 @TruffleLanguage.Registration(id = PythonLanguage.ID, name = PythonLanguage.NAME, version = PythonLanguage.VERSION, mimeType = PythonLanguage.MIME_TYPE, interactive = true, internal = false)
 @ProvidedTags({StandardTags.CallTag.class, StandardTags.StatementTag.class, StandardTags.RootTag.class, StandardTags.TryBlockTag.class, DebuggerTags.AlwaysHalt.class})
 public final class PythonLanguage extends TruffleLanguage<PythonContext> {
-
     public static final String ID = "python";
     public static final String NAME = "Python";
     public static final int MAJOR = 3;
     public static final int MINOR = 7;
     public static final int MICRO = 0;
     public static final String VERSION = MAJOR + "." + MINOR + "." + MICRO;
 
-    public static final String MIME_TYPE = "application/x-python";
+    public static final String MIME_TYPE = "text/x-python";
     public static final String EXTENSION = ".py";
 
     @CompilationFinal private PythonCore sharedCore;