Remove DirectoryException and LinkException from dart:io and use FileException instaed.

tests/standalone/io/file_read_encoded_test.dart

Index: tests/standalone/io/file_read_encoded_test.dart
diff --git a/tests/standalone/io/file_read_encoded_test.dart b/tests/standalone/io/file_read_encoded_test.dart
index 75d4be61b1a90945ce95c84d5ac682e36ee7257f..984b36637a0567747de9893d4efe088ba5d6c538 100644
--- a/tests/standalone/io/file_read_encoded_test.dart
+++ b/tests/standalone/io/file_read_encoded_test.dart
@@ -14,7 +14,7 @@ void testReadAsString() {
 
   file.writeAsBytesSync([0xb0]);
 
-  Expect.throws(file.readAsStringSync, (e) => e is FileException);
+  Expect.throws(file.readAsStringSync, (e) => e is FileSystemException);
 
   asyncStart();
   file.readAsString().then((_) {
@@ -22,7 +22,7 @@ void testReadAsString() {
   }).catchError((e) {
     tmp.deleteSync(recursive: true);
     asyncEnd();
-  }, test: (e) => e is FileException);
+  }, test: (e) => e is FileSystemException);
 }
 
 void testReadAsLines() {
@@ -33,7 +33,7 @@ void testReadAsLines() {
 
   file.writeAsBytesSync([0xb0]);
 
-  Expect.throws(file.readAsLinesSync, (e) => e is FileException);
+  Expect.throws(file.readAsLinesSync, (e) => e is FileSystemException);
 
   asyncStart();
   file.readAsLines().then((_) {
@@ -41,7 +41,7 @@ void testReadAsLines() {
   }).catchError((e) {
     tmp.deleteSync(recursive: true);
     asyncEnd();
-  }, test: (e) => e is FileException);
+  }, test: (e) => e is FileSystemException);
 }
 
 void main() {