Fixed unreachable code in tests.

tests/cases/conformance/types/stringLiteral/stringLiteralCheckedInIf01.ts

@@ -12,6 +12,4 @@ function f(foo: T) {
     else { 
         return (foo as S[])[0];
     }
-
-    throw new Error("Unreachable code hit.");
 }

tests/cases/conformance/types/stringLiteral/stringLiteralCheckedInIf02.ts

@@ -13,6 +13,4 @@ function f(foo: T) {
     else { 
         return foo[0];
     }
-
-    throw new Error("Unreachable code hit.");
 }