Undo #39258 (isArray changes) see overview at #41808 (#41849)

Author: Orta Therox

src/lib/es5.d.ts

@@ -1376,7 +1376,7 @@ interface ArrayConstructor {
     (arrayLength?: number): any[];
     <T>(arrayLength: number): T[];
     <T>(...items: T[]): T[];
-    isArray<T>(arg: T | {}): arg is T extends readonly any[] ? (unknown extends T ? never : readonly any[]) : any[];
+    isArray(arg: any): arg is any[];
     readonly prototype: any[];
 }
 

tests/baselines/reference/consistentUnionSubtypeReduction.js

@@ -67,9 +67,9 @@ export const updateIfChanged = <T>(t: T) => {
 >assign : { <T, U>(target: T, source: U): T & U; <T, U, V>(target: T, source1: U, source2: V): T & U & V; <T, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
 >Array.isArray(u) ? [] : {} : undefined[] | {}
 >Array.isArray(u) : boolean
->Array.isArray : <T>(arg: {} | T) => arg is T extends readonly any[] ? unknown extends T ? never : readonly any[] : any[]
+>Array.isArray : (arg: any) => arg is any[]
 >Array : ArrayConstructor
->isArray : <T>(arg: {} | T) => arg is T extends readonly any[] ? unknown extends T ? never : readonly any[] : any[]
+>isArray : (arg: any) => arg is any[]
 >u : U
 >[] : undefined[]
 >{} : {}

tests/baselines/reference/consistentUnionSubtypeReduction.symbols

@@ -1109,9 +1109,9 @@ define(function () {
 >Array : ArrayConstructor
 
         Array.isArray : function (value) { return Object.prototype.toString.call(value) === '[object Array]'; };
->Array.isArray : <T>(arg: {} | T) => arg is T extends readonly any[] ? unknown extends T ? never : readonly any[] : any[]
+>Array.isArray : (arg: any) => arg is any[]
 >Array : ArrayConstructor
->isArray : <T>(arg: {} | T) => arg is T extends readonly any[] ? unknown extends T ? never : readonly any[] : any[]
+>isArray : (arg: any) => arg is any[]
 >function (value) { return Object.prototype.toString.call(value) === '[object Array]'; } : (value: any) => boolean
 >value : any
 >Object.prototype.toString.call(value) === '[object Array]' : boolean