Reapply "[mlir][transform] Support symlinks in module loading. Reorganize tests. (llvm#69329)"

This reverts commit c122b97 but fixes
tests that were added between submitting llvm#69329 for review and landing
it for the first time.

Author: ingomueller-net

mlir/lib/Dialect/Transform/Transforms/TransformInterpreterUtils.cpp

@@ -61,7 +61,8 @@ LogicalResult transform::detail::expandPathsToMLIRFiles(
          it != itEnd && !ec; it.increment(ec)) {
       const std::string &fileName = it->path();
 
-      if (it->type() != llvm::sys::fs::file_type::regular_file) {
+      if (it->type() != llvm::sys::fs::file_type::regular_file &&
+          it->type() != llvm::sys::fs::file_type::symlink_file) {
         LLVM_DEBUG(DBGS() << "  Skipping non-regular file '" << fileName
                           << "'\n");
         continue;

mlir/test/Dialect/LLVM/lower-to-llvm-e2e-with-top-level-named-sequence.mlir

@@ -3,7 +3,7 @@
 // RUN: mlir-opt %s -test-lower-to-llvm -cse | FileCheck %s
 
 // RUN: mlir-opt %s \
-// RUN:   -transform-preload-library=transform-library-paths=%p/../Transform/Library/lower-to-llvm.mlir \
+// RUN:   -transform-preload-library=transform-library-paths=%p/../Transform/include/Library/lower-to-llvm.mlir \
 // RUN:   -transform-interpreter="entry-point=entry_point" \
 // RUN:   -test-transform-dialect-erase-schedule \
 // RUN:   -cse \

mlir/test/Dialect/Transform/Library/lower-to-llvm.mlir renamed to mlir/test/Dialect/Transform/include/Library/lower-to-llvm.mlir

@@ -1,4 +1,5 @@
 // RUN: mlir-opt %s
+// No need to check anything else than parsing here, this is being used by another test as data.
 
 /// Schedule to lower to LLVM.
 module @lower_module_to_llvm attributes { transform.with_named_sequence } {

mlir/test/Dialect/Transform/test-interpreter-external-concurrent-source.mlir renamed to mlir/test/Dialect/Transform/include/test-interpreter-external-concurrent-source.mlir

@@ -1,4 +1,5 @@
 // RUN: mlir-opt %s
+// No need to check anything else than parsing here, this is being used by another test as data.
 
 module attributes {transform.with_named_sequence} {
   transform.named_sequence private @private_helper(%arg0: !transform.any_op {transform.readonly}) {

mlir/test/Dialect/Transform/test-interpreter-external-source.mlir renamed to mlir/test/Dialect/Transform/include/test-interpreter-external-source.mlir

@@ -1,4 +1,5 @@
 // RUN: mlir-opt %s
+// No need to check anything else than parsing here, this is being used by another test as data.
 
 module attributes {transform.with_named_sequence} {
   transform.named_sequence @print_message(%arg0: !transform.any_op {transform.readonly})

mlir/test/Dialect/Transform/test-interpreter-external-symbol-def-invalid.mlir renamed to mlir/test/Dialect/Transform/include/test-interpreter-external-symbol-def-invalid.mlir

@@ -1,5 +1,5 @@
 // RUN: mlir-opt %s \
-// RUN:   -transform-preload-library=transform-library-paths=%p%{fs-sep}test-interpreter-library \
+// RUN:   -transform-preload-library=transform-library-paths=%p%{fs-sep}include%{fs-sep}test-interpreter-library \
 // RUN:   -transform-interpreter=entry-point=private_helper \
 // RUN:   -split-input-file -verify-diagnostics
 

mlir/test/Dialect/Transform/test-interpreter-library/definitions-self-contained.mlir renamed to mlir/test/Dialect/Transform/include/test-interpreter-library/definitions-self-contained.mlir

@@ -1,4 +1,4 @@
-// RUN: mlir-opt %s --pass-pipeline="builtin.module(func.func(test-transform-dialect-interpreter{transform-file-name=%p/test-interpreter-external-concurrent-source.mlir}))" \
+// RUN: mlir-opt %s --pass-pipeline="builtin.module(func.func(test-transform-dialect-interpreter{transform-file-name=%p%{fs-sep}include%{fs-sep}test-interpreter-external-concurrent-source.mlir}))" \
 // RUN:             --verify-diagnostics
 
 // Exercising the pass on multiple functions of different lengths that may be