Defer _PyRuntime_Initialize to Py_InitializeFromConfig.

When I was working on my own copy of ``Py_Initialize()`` for my own embedded interpreter that:
- manually sets ``sys.path`` (set to the base name of the exe since I story the python stlib in a zip file in it's win32 resource section)
- Disables the default explicit ``import site`` (set to 0)
- prevents the user site-packages folder from being added (set to 0),

The way I did this was with a direct copy and paste of the code in ``Py_InitializeEx`` and changed a only what I needed to implement my own ``Py_Initialize`` that suited my own needs. I hated how I needed to define ``Py_BUILD_CORE_MODULE`` and include ``#include <internal/pycore_runtime.h>`` And then checked and saw that everything but the if check in ``Py_InitializeEx`` is inside of ``Py_InitializeFromConfig`` and that the if check could be replaced easily with ``Py_IsInitialized``. Because of that I submitted this change to remove the needless code duplication here since ``Py_InitializeFromConfig`` is used anyways. It also might increase performance very slightly as a result as well for free.

Author: AraHaan

Python/pylifecycle.c

@@ -1414,19 +1414,12 @@ Py_InitializeFromConfig(const PyConfig *config)
 void
 Py_InitializeEx(int install_sigs)
 {
-    PyStatus status;
-
-    status = _PyRuntime_Initialize();
-    if (_PyStatus_EXCEPTION(status)) {
-        Py_ExitStatusException(status);
-    }
-    _PyRuntimeState *runtime = &_PyRuntime;
-
-    if (runtime->initialized) {
+    if (Py_IsInitialized() != 0) {
         /* bpo-33932: Calling Py_Initialize() twice does nothing. */
         return;
     }
 
+    PyStatus status;
     PyConfig config;
     _PyConfig_InitCompatConfig(&config);