Normative: Create global properties for sloppy function hosting as vars

This patch removes a case where a synthetic *undefined* was visible
as a result of legacy sloppy-mode function hoisting.

This patch addresses #753

spec.html

@@ -40457,11 +40457,11 @@ <h1>Changes to GlobalDeclarationInstantiation</h1>
               1. Let _F_ be StringValue of the |BindingIdentifier| of |FunctionDeclaration| _f_.
               1. If replacing the |FunctionDeclaration| _f_ with a |VariableStatement| that has _F_ as a |BindingIdentifier| would not produce any Early Errors for _script_, then
                 1. If _envRec_.HasLexicalDeclaration(_F_) is *false*, then
-                  1. Let _fnDefinable_ be ? _envRec_.CanDeclareGlobalFunction(_F_).
+                  1. Let _fnDefinable_ be ? _envRec_.CanDeclareGlobalVar(_F_).
                   1. If _fnDefinable_ is *true*, then
                     1. NOTE: A var binding for _F_ is only instantiated here if it is neither a VarDeclaredName nor the name of another |FunctionDeclaration|.
                     1. If _declaredFunctionOrVarNames_ does not contain _F_, then
-                      1. Perform ? _envRec_.CreateGlobalFunctionBinding(_F_, *undefined*, *false*).
+                      1. Perform ? _envRec_.CreateGlobalVarBinding(_F_, *false*).
                       1. Append _F_ to _declaredFunctionOrVarNames_.
                     1. When the |FunctionDeclaration| _f_ is evaluated, perform the following steps in place of the |FunctionDeclaration| Evaluation algorithm provided in <emu-xref href="#sec-function-definitions-runtime-semantics-evaluation"></emu-xref>:
                       1. Let _genv_ be the running execution context's VariableEnvironment.
@@ -40495,15 +40495,15 @@ <h1>Changes to EvalDeclarationInstantiation</h1>
                   1. Let _thisLex_ be _thisLex_'s outer environment reference.
                 1. If _bindingExists_ is *false* and _varEnvRec_ is a global Environment Record, then
                   1. If _varEnvRec_.HasLexicalDeclaration(_F_) is *false*, then
-                    1. Let _fnDefinable_ be ? _varEnvRec_.CanDeclareGlobalFunction(_F_).
+                    1. Let _fnDefinable_ be ? _varEnvRec_.CanDeclareGlobalVar(_F_).
                   1. Else,
                     1. Let _fnDefinable_ be *false*.
                 1. Else,
                   1. Let _fnDefinable_ be *true*.
                 1. If _bindingExists_ is *false* and _fnDefinable_ is *true*, then
                   1. If _declaredFunctionOrVarNames_ does not contain _F_, then
                     1. If _varEnvRec_ is a global Environment Record, then
-                      1. Perform ? _varEnvRec_.CreateGlobalFunctionBinding(_F_, *undefined*, *true*).
+                      1. Perform ? _varEnvRec_.CreateGlobalVarBinding(_F_, *true*).
                     1. Else,
                       1. Let _bindingExists_ be _varEnvRec_.HasBinding(_F_).
                       1. If _bindingExists_ is *false*, then