Revert "[flang] disable memory-allocation-opt.fir test on windows" (#83822)

Reverts #83535
Bug fixed by #83768

Author: jeanPerier

flang/test/Fir/memory-allocation-opt.fir

@@ -1,6 +1,4 @@
 // RUN: fir-opt --memory-allocation-opt="dynamic-array-on-heap=true maximum-array-alloc-size=1024" %s | FileCheck %s
-// FIXME: started crashing on windows https://github.com/llvm/llvm-project/issues/83534
-// UNSUPPORTED: system-windows
 
 // Test for size of array being too big.