[scudo][standalone] Fix tests makefile

[cryptoad]

Summary

A missing STATIC entailed some annoying to debug failures wrt 32 vs 64
binaries. Additionally I noticed I was using the wrong variable (the Scudo
one as opposed to the Scudo Standalone one).

See https://reviews.llvm.org/D58184#1412417 and below for discussion.

[brzycki]

Thank you for helping debug this @cryptoad .

lib/scudo/standalone/tests/CMakeLists.txt

 include_directories(..)
 
 add_custom_target(ScudoUnitTests)
 set_target_properties(ScudoUnitTests PROPERTIES
   FOLDER "Compiler-RT Tests")
 
 set(SCUDO_UNITTEST_CFLAGS
   ${COMPILER_RT_UNITTEST_CFLAGS}
   ${COMPILER_RT_GTEST_CFLAGS}
   -I${COMPILER_RT_SOURCE_DIR}/include
   -I${COMPILER_RT_SOURCE_DIR}/lib
   -I${COMPILER_RT_SOURCE_DIR}/lib/scudo/standalone
   -DGTEST_HAS_RTTI=0)
 
-set(SCUDO_TEST_ARCH ${SCUDO_SUPPORTED_ARCH})
+set(SCUDO_TEST_ARCH ${SCUDO_STANDALONE_SUPPORTED_ARCH})
 
 # gtests requires c++
 set(LINK_FLAGS)
 foreach(lib ${SANITIZER_TEST_CXX_LIBRARIES})
   list(APPEND LINK_FLAGS -l${lib})
 endforeach()
 list(APPEND LINK_FLAGS -pthread)
 
 set(TEST_HEADERS)
 foreach (header ${SCUDO_HEADERS})
   list(APPEND TEST_HEADERS ${CMAKE_CURRENT_SOURCE_DIR}/../${header})
 endforeach()
 
 # add_scudo_unittest(<name>
 #                   SOURCES <sources list>
 #                   HEADERS <extra headers list>)
 macro(add_scudo_unittest testname)
   cmake_parse_arguments(TEST "" "" "SOURCES;HEADERS" ${ARGN})
   if(COMPILER_RT_HAS_SCUDO_STANDALONE)
     foreach(arch ${SCUDO_TEST_ARCH})
       set(ScudoUnitTestsObjects)
-      add_library("RTScudoStandalone.test.${arch}"
+      add_library("RTScudoStandalone.test.${arch}" STATIC
         $<TARGET_OBJECTS:RTScudoStandalone.${arch}>)
       generate_compiler_rt_tests(ScudoUnitTestsObjects ScudoUnitTests
         "${testname}-${arch}-Test" ${arch}
         SOURCES ${TEST_SOURCES} ${COMPILER_RT_GTEST_SOURCE}
         COMPILE_DEPS ${TEST_HEADERS}
         DEPS gtest scudo_standalone
         RUNTIME RTScudoStandalone.test.${arch}
         CFLAGS ${SCUDO_UNITTEST_CFLAGS}