Remove now-unnecessary Autovacuum[Launcher|Worker]IAm functions

After commit fd5e8b440d, InitProcess() is called later in the
EXEC_BACKEND startup sequence, so it's enough to set the
am_autovacuum_[launcher|worker] variables at the same place as in the
!EXEC_BACKEND case.

src/backend/postmaster/autovacuum.c

@@ -386,15 +386,6 @@ avlauncher_forkexec(void)
 
 	return postmaster_forkexec(ac, av);
 }
-
-/*
- * We need this set from the outside, before InitProcess is called
- */
-void
-AutovacuumLauncherIAm(void)
-{
-	am_autovacuum_launcher = true;
-}
 #endif
 
 /*
@@ -1453,15 +1444,6 @@ avworker_forkexec(void)
 
 	return postmaster_forkexec(ac, av);
 }
-
-/*
- * We need this set from the outside, before InitProcess is called
- */
-void
-AutovacuumWorkerIAm(void)
-{
-	am_autovacuum_worker = true;
-}
 #endif
 
 /*

src/backend/postmaster/postmaster.c

@@ -4842,12 +4842,6 @@ SubPostmasterMain(int argc, char *argv[])
 	else
 		PGSharedMemoryNoReAttach();
 
-	/* autovacuum needs this set before calling InitProcess */
-	if (strcmp(argv[1], "--forkavlauncher") == 0)
-		AutovacuumLauncherIAm();
-	if (strcmp(argv[1], "--forkavworker") == 0)
-		AutovacuumWorkerIAm();
-
 	/* Read in remaining GUC variables */
 	read_nondefault_variables();
 

src/include/postmaster/autovacuum.h

@@ -66,8 +66,6 @@ extern void AutoVacWorkerFailed(void);
 #ifdef EXEC_BACKEND
 extern void AutoVacLauncherMain(int argc, char *argv[]) pg_attribute_noreturn();
 extern void AutoVacWorkerMain(int argc, char *argv[]) pg_attribute_noreturn();
-extern void AutovacuumWorkerIAm(void);
-extern void AutovacuumLauncherIAm(void);
 #endif
 
 extern bool AutoVacuumRequestWork(AutoVacuumWorkItemType type,