[mlir][aarch64] Remove LIT config for lli (#89545)

This change will only affect MLIR integration tests to be run on
AArch64. When originally introduced, these tests would run with `lli`.
Those tests has since been updated to use `mlir-cpu-runner` instead, see
e.g.:

  * https://reviews.llvm.org/D155405
  * https://reviews.llvm.org/D146917

This patch removes all the leftover `lli` configuration in LIT that's
currently not needed (and is unlikely to be needed any time soon).

Author: banach-space

mlir/test/Integration/lit.local.cfg

@@ -4,15 +4,14 @@ if not config.mlir_include_integration_tests:
     config.unsupported = True
 
 
-def configure_aarch64_lli_and_mcr_cmd():
-    lli_cmd = "lli"
+def configure_aarch64_mcr_cmd():
     mcr_cmd = "mlir-cpu-runner"
 
     # NOTE: If the SVE tests are disabled and the SME tests are enabled to run
     # under emulation, the SVE specific RUN lines in the SparseTensor tests
     # will run under emulation.
     if not (config.mlir_run_arm_sve_tests or config.mlir_run_arm_sme_tests):
-        return (lli_cmd, mcr_cmd)
+        return mcr_cmd
 
     config.substitutions.append(
         (
@@ -22,20 +21,6 @@ def configure_aarch64_lli_and_mcr_cmd():
     )
 
     if config.arm_emulator_executable:
-        if config.arm_emulator_lli_executable:
-            lli_cmd = config.arm_emulator_lli_executable
-        else:
-            # Top-level lit config adds llvm_tools_dir to PATH but this is lost
-            # when running under an emulator. If the user didn't specify an lli
-            # executable, use absolute path %llvm_tools_dir/lli.
-            lli_cmd = llvm_config.use_llvm_tool(
-                "lli",
-                search_env="LLI",
-                required=True,
-                search_paths=[config.llvm_tools_dir],
-                use_installed=False,
-            )
-
         if config.arm_emulator_mlir_cpu_runner_executable:
             mcr_cmd = config.arm_emulator_mlir_cpu_runner_executable
         else:
@@ -56,35 +41,20 @@ def configure_aarch64_lli_and_mcr_cmd():
             f"{config.arm_emulator_executable} {config.arm_emulator_options}"
         )
 
-        lli_cmd = f"{emulation_cmd} {lli_cmd}"
         mcr_cmd = f"{emulation_cmd} {mcr_cmd}"
 
-    return (lli_cmd, mcr_cmd)
+    return mcr_cmd
 
 
-aarch64_lli_cmd, aarch64_mcr_cmd = configure_aarch64_lli_and_mcr_cmd()
+aarch64_mcr_cmd = configure_aarch64_mcr_cmd()
 
-# Configure the following AArch64 substitutions:
-#
-# * %lli_aarch64_cmd         - Invokes lli. For tests that _will_ run on AArch64 (ArmSVE, ArmSME).
-# * %lli_host_or_aarch64_cmd - Invokes lli. For tests that _may_ run on AArch64 (SparseTensor).
-# * %mcr_aarch64_cmd         - Invokes mlir-cpu-runner. For tests that _will_
-#                              run on AArch64. May invoke mlir-cpu-runner under
-#                              an AArch64 emulator (when
-#                              `config.arm_emulator_executable` is set).
-#
 # AArch64 tests will run under emulation if configured at build time by the
 # following CMake options:
 #
 # * ARM_EMULATOR_EXECUTABLE     - emulator to use.
 # * ARM_EMULATOR_OPTIONS        - options for emulator.
-# * ARM_EMULATOR_LLI_EXECUTABLE - AArch64 native lli to support cross-compilation.
-# * ARM_EMULATOR_UTILS_LIB_DIR  - AArch64 native utilites library to support cross-compilation.
-#
-# Functionally the two substitutions are equivalent, i.e. %lli_aarch64_cmd
-# could be used in the SparseTensor tests where necessary, but the meaning
-# conveyed by the substitution name would be a misnomer if the host target
-# is not AArch64 and MLIR_RUN_ARM_SVE_TESTS=OFF.
-config.substitutions.append(("%lli_aarch64_cmd", aarch64_lli_cmd))
-config.substitutions.append(("%lli_host_or_aarch64_cmd", aarch64_lli_cmd))
+# * ARM_EMULATOR_MLIR_CPU_RUNNER_EXECUTABLE - AArch64 native mlir-cpu-runner to
+#                                             support cross-compilation
+# * ARM_EMULATOR_UTILS_LIB_DIR - AArch64 native utilites library to support
+#                                cross-compilation.
 config.substitutions.append(("%mcr_aarch64_cmd", aarch64_mcr_cmd))