[flang][OpenMP] Enable delayed privatization by default for omp.distribute (#131574)

Switches delayed privatization for `omp.distribute` to be on by default:
controlled by the `-openmp-enable-delayed-privatization` instead of by
`-openmp-enable-delayed-privatization-staging`.

### GFortran & Fujitsu test suite results:

#### gfotran test-suite (this PR):
```
Testing Time: 34.51s
  Passed: 6569
```

#### Fujitsu without changes (commit: 0813c5c):
```
Testing Time: 155.39s
  Passed            : 88325
  Failed            :   156
  Executable Missing:   408
```

#### Fujitsu with changes (this PR):
```
Testing Time: 158.54s
  Passed            : 88325
  Failed            :   156
  Executable Missing:   408
```

Author: ergawy

flang/lib/Lower/OpenMP/OpenMP.cpp

@@ -2549,7 +2549,7 @@ static void genStandaloneDistribute(lower::AbstractConverter &converter,
 
   DataSharingProcessor dsp(converter, semaCtx, item->clauses, eval,
                            /*shouldCollectPreDeterminedSymbols=*/true,
-                           enableDelayedPrivatizationStaging, symTable);
+                           enableDelayedPrivatization, symTable);
   dsp.processStep1(&distributeClauseOps);
 
   mlir::omp::LoopNestOperands loopNestClauseOps;

flang/test/Lower/OpenMP/distribute.f90

@@ -7,7 +7,7 @@ subroutine distribute_simple()
   ! CHECK: omp.teams
   !$omp teams
 
-  ! CHECK: omp.distribute {
+  ! CHECK: omp.distribute private({{.*}}) {
   !$omp distribute
 
   ! CHECK-NEXT: omp.loop_nest

flang/test/Lower/OpenMP/order-clause.f90

@@ -61,15 +61,15 @@ end subroutine do_simd_order_parallel
 
 
 subroutine distribute_order
-   !CHECK: omp.distribute order(reproducible:concurrent) {
+   !CHECK: omp.distribute order(reproducible:concurrent) private({{.*}}) {
    !$omp teams distribute order(concurrent)
    do i=1,10
    end do
-   !CHECK: omp.distribute order(reproducible:concurrent) {
+   !CHECK: omp.distribute order(reproducible:concurrent) private({{.*}}) {
    !$omp teams distribute order(reproducible:concurrent)
    do i=1,10
    end do
-   !CHECK: omp.distribute order(unconstrained:concurrent) {
+   !CHECK: omp.distribute order(unconstrained:concurrent) private({{.*}}) {
    !$omp teams distribute order(unconstrained:concurrent)
    do i = 1, 10
    end do

flang/test/Transforms/stack-arrays-hlfir.f90

@@ -73,7 +73,7 @@ end subroutine omp_target_wsloop
 ! CHECK-NOT:       fir.freemem
 ! CHECK:         omp.teams {
 ! CHECK:           fir.alloca !fir.array<2xi64>
-! CHECK:         omp.distribute {
+! CHECK:         omp.distribute private({{.*}}) {
 ! CHECK:         omp.loop_nest {{.*}} {
 ! CHECK-NOT:       fir.allocmem
 ! CHECK-NOT:       fir.freemem