Test:contextual typing of arguments obj in JS files

tests/baselines/reference/contextuallyTypeArgumentsKeyword.symbols

@@ -0,0 +1,14 @@
+=== tests/cases/compiler/foo.js ===
+// Repro for #16585
+const x = {
+>x : Symbol(x, Decl(foo.js, 1, 5))
+
+    bar() {
+>bar : Symbol(bar, Decl(foo.js, 1, 11))
+
+        setTimeout(function() { arguments }, 0);
+>setTimeout : Symbol(setTimeout, Decl(lib.dom.d.ts, --, --), Decl(lib.dom.d.ts, --, --))
+>arguments : Symbol(arguments)
+    }
+}
+

tests/baselines/reference/contextuallyTypeArgumentsKeyword.types

@@ -0,0 +1,18 @@
+=== tests/cases/compiler/foo.js ===
+// Repro for #16585
+const x = {
+>x : { [x: string]: any; bar(): void; }
+>{    bar() {        setTimeout(function() { arguments }, 0);    }} : { [x: string]: any; bar(): void; }
+
+    bar() {
+>bar : () => void
+
+        setTimeout(function() { arguments }, 0);
+>setTimeout(function() { arguments }, 0) : number
+>setTimeout : { (handler: (...args: any[]) => void, timeout: number): number; (handler: any, timeout?: any, ...args: any[]): number; }
+>function() { arguments } : (...args: any[]) => void
+>arguments : IArguments
+>0 : 0
+    }
+}
+

tests/cases/compiler/contextuallyTypeArgumentsKeyword.ts

@@ -0,0 +1,11 @@
+// @noEmit: true
+// @allowJs: true
+// @checkJs: true
+// @lib: es2017, dom
+// @Filename: foo.js
+// Repro for #16585
+const x = {
+    bar() {
+        setTimeout(function() { arguments }, 0);
+    }
+}