Move the "convertEs6TypedToEs6" to the very start of compilation.

This change is to prevent passes which don't support TS syntax features (essentially all of them) from ever receiving code containing those features. Currently those passes ignore this condition, however a followup change will make that an error.

It is also necessary to update how the pass operates on rest parameters. Previously, it was generating unrecognized type annotations; they were being attached to the wrong node. This has been corrected.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=232744013

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

@@ -241,6 +241,10 @@ private void addTypeCheckerPasses(List<PassFactory> checks, CompilerOptions opti
   protected List<PassFactory> getChecks() {
     List<PassFactory> checks = new ArrayList<>();
 
+    if (options.needsTranspilationFrom(TYPESCRIPT)) {
+      checks.add(convertEs6TypedToEs6);
+    }
+
     checks.add(gatherGettersAndSetters);
 
     if (options.shouldGenerateTypedExterns()) {
@@ -268,10 +272,6 @@ protected List<PassFactory> getChecks() {
     // Verify JsDoc annotations and check ES6 modules
     checks.add(checkJsDocAndEs6Modules);
 
-    if (options.needsTranspilationFrom(TYPESCRIPT)) {
-      checks.add(convertEs6TypedToEs6);
-    }
-
     checks.add(checkTypeImportCodeReferences);
 
     checks.add(gatherModuleMetadataPass);

src/com/google/javascript/jscomp/Es6TypedToEs6Converter.java

@@ -157,9 +157,11 @@ public void visit(NodeTraversal t, Node n, Node parent) {
         visitEnum(t, n, parent);
         break;
       case NAME:
-      case REST:
         maybeVisitColonType(t, n, n);
         break;
+      case REST:
+        maybeVisitColonType(t, n, n.getOnlyChild());
+        break;
       case FUNCTION:
         visitFunction(t, n, parent);
         break;

test/com/google/javascript/jscomp/Es6TypedToEs6ConverterTest.java

@@ -237,27 +237,28 @@ public void testOptionalProperty_withES6Modules() {
 
   @Test
   public void testRestParameter() {
-    test("function f(...p1: number[]) {}", "function f(/** ...number */ ...p1) {}");
+    test("function f(...p1: number[]) {}", "function f(.../** ...number */ p1) {}");
     testSame("function f(...p1) {}");
   }
 
   @Test
   public void testRestParameter_withES6Modules() {
-    test("export function f(...p1: number[]) {}", "export function f(/** ...number */ ...p1) {}");
+    test("export function f(...p1: number[]) {}", "export function f(.../** ...number */ p1) {}");
   }
 
   @Test
   public void testReturnType() {
-    test("function f(...p1: number[]): void {}",
-         "/** @return{void} */ function f(/** ...number */ ...p1) {}");
+    test(
+        "function f(...p1: number[]): void {}",
+        "/** @return{void} */ function f(.../** ...number */ p1) {}");
     testSame("function f(...p1) {}");
   }
 
   @Test
   public void testReturnType_withES6Modules() {
     test(
         "export function f(...p1: number[]): void {}",
-        "export /** @return{void} */ function f(/** ...number */ ...p1) {}");
+        "export /** @return{void} */ function f(.../** ...number */ p1) {}");
   }
 
   @Test