Make anyArray.filter(Boolean) return any[], not unknown[] (#31515)

* Add this-parameter workaround to Array.filter

Allows anys.filter(Boolean) to once again return any[], not unknown[].

* Add any constraint to Boolean factory function

I want to test how well this works.

* Remove Boolean factory type guard

* Remove typeGuardBoolean test

tests/cases/compiler/booleanFilterAnyArray.ts

@@ -0,0 +1,24 @@
+interface Bullean { }
+interface BulleanConstructor {
+    new(v1?: any): Bullean;
+    <T>(v2?: T): v2 is T;
+}
+
+interface Ari<T> {
+    filter<S extends T>(cb1: (value: T) => value is S): T extends any ? Ari<any> : Ari<S>;
+    filter(cb2: (value: T) => unknown): Ari<T>;
+}
+declare var Bullean: BulleanConstructor;
+declare let anys: Ari<any>;
+var xs: Ari<any>;
+var xs = anys.filter(Bullean)
+
+declare let realanys: any[];
+var ys: any[];
+var ys = realanys.filter(Boolean)
+
+var foo = [{ name: 'x' }]
+var foor: Array<{name: string}>
+var foor = foo.filter(x => x.name)
+var foos: Array<boolean>
+var foos = [true, true, false, null].filter((thing): thing is boolean => thing !== null)

tests/cases/conformance/expressions/typeGuards/typeGuardBoolean.ts

@@ -1,14 +0,0 @@
-// @strictNullChecks: true
-function test(strOrNull: string | null, strOrUndefined: string | undefined) {
-  var str: string = "original";
-  var nil: null;
-  if (!Boolean(strOrNull)) {
-      nil = strOrNull;
-  }
-  else {
-      str = strOrNull;
-  }
-  if (Boolean(strOrUndefined)) {
-      str = strOrUndefined;
-  }
-}