Transition typedAstOutputFile from a stream to a Path.

Streams are not good fields in options.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=258491821

src/com/google/javascript/jscomp/CompilerOptions.java

@@ -144,15 +144,15 @@ public boolean getInstrumentForCoverageOnly() {
     return instrumentForCoverageOnly;
   }
 
-  @Nullable private OutputStream typedAstOutputFile = null;
+  @Nullable private Path typedAstOutputFile = null;
 
   /** Sets file to output in-progress TypedAST format to. DO NOT USE! */
-  void setTypedAstOutputFile(@Nullable OutputStream file) {
+  void setTypedAstOutputFile(@Nullable Path file) {
     this.typedAstOutputFile = file;
   }
 
   @Nullable
-  OutputStream getTypedAstOutputFile() {
+  Path getTypedAstOutputFile() {
     return this.typedAstOutputFile;
   }
 

src/com/google/javascript/jscomp/gwt/super/com/google/javascript/jscomp/serialization/SerializeTypedAstPass.java

@@ -19,12 +19,12 @@
 import com.google.javascript.jscomp.AbstractCompiler;
 import com.google.javascript.jscomp.CompilerPass;
 import com.google.javascript.rhino.Node;
-import java.io.OutputStream;
+import java.nio.file.Path;
 
 /** Fail-fast replacement */
 public final class SerializeTypedAstPass implements CompilerPass {
 
-  public SerializeTypedAstPass(AbstractCompiler compiler, OutputStream out) {
+  public SerializeTypedAstPass(AbstractCompiler compiler, Path out) {
     throw new RuntimeException("Serialization not yet supported in JS version of compiler");
   }