gh-107211: No longer export internal functions (3) (#107215)

No longer export these 14 internal C API functions:

* _PySys_Audit()
* _PySys_SetAttr()
* _PyTraceBack_FromFrame()
* _PyTraceBack_Print_Indented()
* _PyUnicode_FormatAdvancedWriter()
* _PyUnicode_ScanIdentifier()
* _PyWarnings_Init()
* _Py_DumpASCII()
* _Py_DumpDecimal()
* _Py_DumpHexadecimal()
* _Py_DumpTraceback()
* _Py_DumpTracebackThreads()
* _Py_WriteIndent()
* _Py_WriteIndentedMargin()