fix(core): Removed depricated disposePlatform

BREAKING CHANGE: previously deprecated disposePlatform was removed; see deprecation notice for migration instructions.

tools/public_api_guard/core/index.d.ts

@@ -488,6 +488,9 @@ export declare class DefaultIterableDiffer implements IterableDiffer {
     toString(): string;
 }
 
+/** @experimental */
+export declare function destroyPlatform(): void;
+
 /** @stable */
 export declare var Directive: DirectiveMetadataFactory;
 
@@ -532,9 +535,6 @@ export interface DirectiveMetadataType {
     selector?: string;
 }
 
-/** @deprecated */
-export declare function disposePlatform(): void;
-
 /** @stable */
 export declare abstract class DoCheck {
     abstract ngDoCheck(): void;