Don't freeze internal instantiation of builtins and string constants

Author: eqrion

document/js-api/index.bs

@@ -415,7 +415,6 @@ To <dfn>instantiate imported strings</dfn> with module |module| and |importedStr
     1. Let |stringConstant| be |componentName|.
     1. Let |status| be [=!=] [$CreateDataProperty$](|exportsObject|, |stringConstant|, |stringConstant|).
     1. Assert: |status| is true.
-1. Perform [=!=] [$SetIntegrityLevel$](|exportsObject|, `"frozen"`).
 1. Return |exportsObject|.
 
 </div>
@@ -1776,7 +1775,6 @@ To <dfn>instantiate a builtin set</dfn> with name |builtinSetName|, perform the
     1. Let |value| be |func|.
     1. Let |status| be [=!=] [$CreateDataProperty$](|exportsObject|, |name|, |value|).
     1. Assert: |status| is true.
-1. Perform [=!=] [$SetIntegrityLevel$](|exportsObject|, `"frozen"`).
 1. Return |exportsObject|.
 
 </div>