vbscript: Fixed chr(0) implementation.

dlls/vbscript/global.c

@@ -1088,7 +1088,7 @@ static HRESULT Global_Chr(vbdisp_t *This, VARIANT *arg, unsigned args_cnt, VARIA
     if(FAILED(hres))
         return hres;
 
-    if(c <= 0 || c >= 0x100) {
+    if(c < 0 || c >= 0x100) {
         FIXME("invalid arg\n");
         return E_FAIL;
     }

dlls/vbscript/tests/api.vbs

@@ -119,6 +119,7 @@ if isEnglishLang then TestCStr true, "True"
 Call ok(getVT(Chr(120)) = "VT_BSTR", "getVT(Chr(120)) = " & getVT(Chr(120)))
 Call ok(getVT(Chr(255)) = "VT_BSTR", "getVT(Chr(255)) = " & getVT(Chr(255)))
 Call ok(Chr(120) = "x", "Chr(120) = " & Chr(120))
+Call ok(Chr(0) <> "", "Chr(0) = """"")
 
 Call ok(isObject(new EmptyClass), "isObject(new EmptyClass) is not true?")
 Set x = new EmptyClass