[libFuzzer] Fix multi-arch build support for fuzzer tests.

[george.karpenkov]

Summary

The bug was not previously exposed as only one architecture is currently

supported for libFuzzer.

test/fuzzer/CMakeLists.txt

foreach(arch ${FUZZER_SUPPORTED_ARCH})
     set(CONFIG_NAME ${ARCH_UPPER_CASE}${STDLIB_CAPITALIZED}${OS_NAME}Config)
 
     # LIT-based libFuzzer tests.
     configure_lit_site_cfg(
       ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.in
       ${CMAKE_CURRENT_BINARY_DIR}/${CONFIG_NAME}/lit.site.cfg
       )
 
-    add_lit_testsuite(check-fuzzer-${stdlib_name} "Running Fuzzer ${stdlib} tests"
-      ${CMAKE_CURRENT_BINARY_DIR}/${CONFIG_NAME}
+    add_lit_testsuite(check-fuzzer-${stdlib_name}-${arch}
+      "Running Fuzzer ${stdlib} tests"
+      ${CMAKE_CURRENT_BINARY_DIR}/${CONFIG_NAME}/
       DEPENDS ${LIBFUZZER_TEST_DEPS})
     if(TEST_DEPS)
-      add_dependencies(check-fuzzer-${stdlib_name} ${TEST_DEPS})
+      add_dependencies(check-fuzzer-${stdlib_name}-${arch} ${TEST_DEPS})
     endif()
-    set_target_properties(check-fuzzer-${stdlib_name} PROPERTIES FOLDER "Compiler-RT Tests")
-    add_dependencies(check-fuzzer check-fuzzer-${stdlib_name})
+    set_target_properties(check-fuzzer-${stdlib_name}-${arch}
+        PROPERTIES FOLDER "Compiler-RT Tests")
+    add_dependencies(check-fuzzer check-fuzzer-${stdlib_name}-${arch})
   endforeach()
 endmacro()
 
 test_fuzzer("default")
 if("${CMAKE_SYSTEM_NAME}" STREQUAL "Linux")
   if(TARGET cxx_shared)
     test_fuzzer("libc++" DEPS cxx_shared)
   endif()
   if(TARGET cxx_static)
     test_fuzzer("static-libc++" DEPS cxx_static)
   endif()
 endif()