mapi: do not call thread-unsafe dispatch getter

When not using the USE_ELF_TLS code-path, this function is
thread-unsafe, because it returns u_current_table if set without
consulting the ThreadSafe variable in u_current.c.

There's a short period where this can cause problems, if a program uses
multiple threads, but only have made a single context current so far. If
the program issues OpenGL commands from the initialized thread while a
new thread is setting u_current_table to __glapi_noop_table, we will
return the wrong table here.

It doesn't seem right to have two versions of the code that does the
same anyway, so let's use the version that doesn't have this problem
instead.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Louis-Francis Ratté-Boulianne <lfrb@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7280>

src/mapi/entry.c

@@ -67,7 +67,7 @@ entry_current_get(void)
 #ifdef MAPI_MODE_BRIDGE
    return GET_DISPATCH();
 #else
-   return u_current_get_table();
+   return u_current_get_table_internal();
 #endif
 }
 

src/mapi/u_current.h

@@ -62,15 +62,4 @@ u_current_set_context(const void *ptr);
 void *
 u_current_get_context_internal(void);
 
-static inline const struct _glapi_table *
-u_current_get_table(void)
-{
-#ifdef USE_ELF_TLS
-   return u_current_table;
-#else
-   return (likely(u_current_table) ?
-         u_current_table : u_current_get_table_internal());
-#endif
-}
-
 #endif /* _U_CURRENT_H_ */