* objGlue.t test extension: check for cget() return value
* Tcl_GetStringFromObj: simplified utf8 repair code

  The utf8Whoops() function is gone; it doesn't do anything different
  than a sv_utf8_upgrade + sv_dump, something which is already done a
  few lines before.

  Also, as the t/objglue.t test script touches a code path calling
  LangDebug+sv_dump (since perl 5.17.x), the debugging calls are now
  removed to reduce noise in the test suite (it seems that things
  still work anyway).