MLIR: asan: Fix python tests under asan on Linux (llvm#123303)

Running MLIR python tests unders asan currently fails with
```
executed command: 'LD_PRELOAD=$(/usr/bin/clang++-17' '-print-file-name=libclang_rt.asan-x86_64.so)' /scratch/slx-llvm/.venv-3.10/bin/python3.10 /scratch/slx-llvm/mlir/test/python/ir/context_lifecycle.py

| 'LD_PRELOAD=$(/usr/bin/clang++-17': command not found
```
because lit doesn't quite understand the syntax.
To fix, we resolve the path to `libclang_rt.asan-x86_64.so` within the
lit configuration. This has the additional benefit that we don't have to
call `clang++` for every test.

Co-authored-by: Philipp-Jan Honysz <[email protected]>

Author: mgehre-amd

mlir/test/lit.cfg.py

@@ -82,17 +82,32 @@ def add_runtime(name):
 # available. This is darwin specific since it's currently only needed on darwin.
 # Stolen from llvm/test/lit.cfg.py with a few modifications
 def get_asan_rtlib():
-    if not "asan" in config.available_features or not "Darwin" in config.host_os:
+    if not "asan" in config.available_features:
         return ""
-    # Find the asan rt lib
-    resource_dir = (
-        subprocess.check_output([config.host_cc.strip(), "-print-resource-dir"])
-        .decode("utf-8")
-        .strip()
-    )
-    return os.path.join(
-        resource_dir, "lib", "darwin", "libclang_rt.asan_osx_dynamic.dylib"
-    )
+
+    if "Darwin" in config.host_os:
+        # Find the asan rt lib
+        resource_dir = (
+            subprocess.check_output([config.host_cc.strip(), "-print-resource-dir"])
+            .decode("utf-8")
+            .strip()
+        )
+        return os.path.join(
+            resource_dir, "lib", "darwin", "libclang_rt.asan_osx_dynamic.dylib"
+        )
+    if "Linux" in config.host_os:
+        return (
+            subprocess.check_output(
+                [
+                    config.host_cxx.strip(),
+                    f"-print-file-name=libclang_rt.asan-{config.host_arch}.so",
+                ]
+            )
+            .decode("utf-8")
+            .strip()
+        )
+
+    return ""
 
 
 # On macOS, we can't do the DYLD_INSERT_LIBRARIES trick with a shim python
@@ -247,7 +262,9 @@ def find_real_python_interpreter():
 # TODO: detect Windows situation (or mark these tests as unsupported on these platforms).
 if "asan" in config.available_features:
     if "Linux" in config.host_os:
-        python_executable = f"LD_PRELOAD=$({config.host_cxx} -print-file-name=libclang_rt.asan-{config.host_arch}.so) {config.python_executable}"
+        python_executable = (
+            f"env LD_PRELOAD={get_asan_rtlib()} {config.python_executable}"
+        )
     if "Darwin" in config.host_os:
         # Ensure we use a non-shim Python executable, for the `DYLD_INSERT_LIBRARIES`
         # env variable to take effect