Revert "GC_fullCollect on sync threadpool (#6107)" (#6119)
Revert "GC_fullCollect on sync threadpool (#6107)" (#6119)

This reverts commit bdb653c4156af099814df2e21b9878cdb1591190.
russpowers/Nim,tulayang/Nim,tulayang/Nim,dom96/Nim,dom96/Nim,dom96/Nim,russpowers/Nim,russpowers/Nim,tulayang/Nim,russpowers/Nim,dom96/Nim,dom96/Nim,russpowers/Nim,russpowers/Nim,russpowers/Nim,tulayang/Nim,dom96/Nim,tulayang/Nim,dom96/Nim,tulayang/Nim