Move transpilation of rest/spread after the post-typecheck check passes.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=201435647

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

@@ -118,7 +118,6 @@ static void addPreTypecheckTranspilationPasses(
         // support the transpiled features.
         // TODO(b/73387406): Move each pass above here temporarily, then into
         // addEs6PostCheck Passes once the pass supports propagating type information
-        passes.add(es6RewriteRestAndSpread);
       }
     }
   }
@@ -140,6 +139,7 @@ public static void addPostCheckTranspilationPasses(List<PassFactory> passes) {
     // TODO(b/73387406): Move passes here as typechecking & other check passes are updated to cope
     // with the features they transpile and as the passes themselves are updated to propagate type
     // information to the transpiled code.
+    passes.add(es6RewriteRestAndSpread);
     passes.add(lateConvertEs6ToEs3);
     passes.add(es6ForOf);
     passes.add(rewriteBlockScopedFunctionDeclaration);

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

@@ -2476,15 +2476,10 @@ public void testRestParameterWithTemplateType() {
             "}",
             "/** @type {null} */ var a = firstOf('hi', 1);",
             ""),
-        ImmutableList.of(
-            // TODO(b/79707793): This will be fixed when transpilation of REST parameters moves
-            // after type checking.
-            "Bad type annotation. Unknown type T",
-            lines(
-                "initializing variable", // preserve newlinues
-                "found   : (number|string)",
-                "required: null")),
-        /* isError= */ false);
+        lines(
+            "initializing variable", // preserve newlines
+            "found   : (number|string)",
+            "required: null"));
   }
 
   // Test that when transpiling we don't use T in the body of f; it would cause a spurious