Delete obsolete tests/microbenchmarks/ folder. (iree-org#18051)

As far as I can tell from the history in
https://github.com/iree-org/iree/commits/main/tests/microbenchmarks,
these haven't been modified in 2 years.

These targets only compile, they don't actually run or benchmark, and
only the ASan CI job even runs that compile step.

CMakeLists.txt

@@ -100,8 +100,6 @@ set(IREE_HOST_BIN_DIR "${IREE_HOST_BIN_DIR_DEFAULT}" CACHE STRING "Path to direc
 option(IREE_BUILD_BINDINGS_TFLITE "Builds the IREE TFLite C API compatibility shim" ON)
 option(IREE_BUILD_BINDINGS_TFLITE_JAVA "Builds the IREE TFLite Java bindings with the C API compatibility shim" ON)
 
-option(IREE_BUILD_MICROBENCHMARKS "Builds IREE microbenchmark suites." OFF)
-
 option(IREE_BUILD_ALL_CHECK_TEST_MODULES "Builds all modules for iree_check_test, regardless of which would be tested" ON)
 
 option(IREE_BUILD_E2E_TEST_ARTIFACTS "Builds IREE E2E test artifacts suite generated by the e2e test framework." "${IREE_BUILD_EXPERIMENTAL_E2E_TEST_ARTIFACTS}")
@@ -571,7 +569,6 @@ include(iree_e2e_generated_runner_test)
 include(iree_native_test)
 include(iree_cc_binary_benchmark)
 include(iree_benchmark_suite)
-include(iree_microbenchmark_suite)
 include(iree_hal_cts_test_suite)
 include(iree_static_linker_test)
 include(iree_fetch_artifact)
@@ -724,11 +721,6 @@ endif()
 # dependencies to them.
 #-------------------------------------------------------------------------------
 
-if(IREE_BUILD_MICROBENCHMARKS)
-  # Add top-level custom targets to drive generating microbenchmark suites.
-  add_custom_target(iree-microbenchmark-suites)
-endif()
-
 if(IREE_BUILD_DOCS)
   # Define a top-level custom target to drive generating documentation files.
   # Add to the default target given that docs were explicitly requested.

build_tools/cmake/build_and_test_asan.sh

@@ -32,7 +32,6 @@ CMAKE_ARGS=(
   "-DPython3_EXECUTABLE=${IREE_PYTHON3_EXECUTABLE}"
   "-DPYTHON_EXECUTABLE=${IREE_PYTHON3_EXECUTABLE}"
   "-DIREE_ENABLE_ASSERTIONS=${IREE_ENABLE_ASSERTIONS}"
-  "-DIREE_BUILD_MICROBENCHMARKS=ON"
 )
 
 echo "::group::Configuring CMake"
@@ -47,10 +46,6 @@ echo "::group::Building test deps"
 "${CMAKE_BIN?}" --build "${BUILD_DIR?}" --target iree-test-deps -- -k 0
 echo "::endgroup::"
 
-echo "::group::Building microbenchmark suites"
-"${CMAKE_BIN?}" --build "${BUILD_DIR?}" --target iree-microbenchmark-suites -- -k 0
-echo "::endgroup::"
-
 if (( IREE_USE_CCACHE == 1 )); then
   ccache --show-stats
 fi