test: add public api golden files

Includes a few style fixes on "* as foo" imports.

tools/public_api_guard/common/testing.d.ts

@@ -0,0 +1,33 @@
+export declare class MockLocationStrategy extends LocationStrategy {
+    internalBaseHref: string;
+    internalPath: string;
+    internalTitle: string;
+    urlChanges: string[];
+    constructor();
+    simulatePopState(url: string): void;
+    path(): string;
+    prepareExternalUrl(internal: string): string;
+    pushState(ctx: any, title: string, path: string, query: string): void;
+    replaceState(ctx: any, title: string, path: string, query: string): void;
+    onPopState(fn: (value: any) => void): void;
+    getBaseHref(): string;
+    back(): void;
+    forward(): void;
+}
+
+export declare class SpyLocation implements Location {
+    urlChanges: string[];
+    setInitialPath(url: string): void;
+    setBaseHref(url: string): void;
+    path(): string;
+    isCurrentPathEqualTo(path: string, query?: string): boolean;
+    simulateUrlPop(pathname: string): void;
+    simulateHashChange(pathname: string): void;
+    prepareExternalUrl(url: string): string;
+    go(path: string, query?: string): void;
+    replaceState(path: string, query?: string): void;
+    forward(): void;
+    back(): void;
+    subscribe(onNext: (value: any) => void, onThrow?: (error: any) => void, onReturn?: () => void): Object;
+    normalize(url: string): string;
+}