Remove immediate pragma (#11308)

* remove immediate from tests
* remove immediate from the compiler

lib/system/alloc.nim

@@ -1063,8 +1063,7 @@ template instantiateForRegion(allocator: untyped) =
       result = realloc(p, newSize)
 
   when hasThreadSupport:
-
-    template sharedMemStatsShared(v: int) {.immediate.} =
+    template sharedMemStatsShared(v: int) =
       acquireSys(heapLock)
       result = v
       releaseSys(heapLock)

lib/system/inclrtl.nim

@@ -19,11 +19,6 @@
 when not defined(nimNewShared):
   {.pragma: gcsafe.}
 
-when not defined(nimImmediateDeprecated):
-  {.pragma: oldimmediate, immediate.}
-else:
-  {.pragma: oldimmediate.}
-
 when defined(createNimRtl):
   when defined(useNimRtl):
     {.error: "Cannot create and use nimrtl at the same time!".}