Guard test customization only if target exists.

This was failing when built with IREE_BUILD_TESTS=OFF (as is done for releases).

compiler/src/iree/compiler/API2/test/CMakeLists.txt

diff --git a/compiler/src/iree/compiler/API2/test/CMakeLists.txt b/compiler/src/iree/compiler/API2/test/CMakeLists.txt
index 74a35cb..dd9f75c 100644
--- a/compiler/src/iree/compiler/API2/test/CMakeLists.txt
+++ b/compiler/src/iree/compiler/API2/test/CMakeLists.txt
@@ -25,8 +25,10 @@
 
 # Move to bin/ directory and systematically name more appropriately.
 # See: https://github.com/iree-org/iree/issues/11297
-set_target_properties(iree_compiler_API2_test_api-test-binary
-  PROPERTIES
-  OUTPUT_NAME "test-iree-compiler-api-test-binary"
-  RUNTIME_OUTPUT_DIRECTORY "${PROJECT_BINARY_DIR}/tools"
-)
+if(TARGET iree_compiler_API2_test_api-test-binary)
+  set_target_properties(iree_compiler_API2_test_api-test-binary
+    PROPERTIES
+    OUTPUT_NAME "test-iree-compiler-api-test-binary"
+    RUNTIME_OUTPUT_DIRECTORY "${PROJECT_BINARY_DIR}/tools"
+  )
+endif()