[compiler-rt][asan] Enable unwind-tables for Arm Linux

[DavidSpickett]

Summary

Since https://reviews.llvm.org/D102046 some tests have
been falling back to fast unwinding on our Thumb bot.

This fails because fast unwinding does not work on Thumb.
By adding the extra information we ensure this does not happen
during testing, but the built library can still fast unwind
as a last resort.

Since there are some situations it can work in, like if
eveything is built with clang. During testing we've got gcc
built system libs and clang built tests.

The same change was made for sanitizer-common in
https://reviews.llvm.org/D96337.

[DavidSpickett]

Remove newline

[DavidSpickett]

https://lab.llvm.org/buildbot/#/builders/26/builds/2096, the sanitizer-common test needs to be handled in its own way since it's disabling things itself.

[zatrazz]

LGTM, thanks.

compiler-rt/test/asan/CMakeLists.txt

if(COMPILER_RT_ASAN_HAS_STATIC_RUNTIME)
     set(ASAN_TEST_DYNAMIC True)
     set(CONFIG_NAME ${ARCH_UPPER_CASE}${OS_NAME}DynamicConfig)
     configure_lit_site_cfg(
       ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.py.in
       ${CMAKE_CURRENT_BINARY_DIR}/${CONFIG_NAME}/lit.site.cfg.py)
     list(APPEND ASAN_DYNAMIC_TESTSUITES
       ${CMAKE_CURRENT_BINARY_DIR}/${CONFIG_NAME})
   endif()
+
+  # ARM on Linux may include thumb code, where fast unwinding does not work.
+  # Enable unwind tables so that we do not end up falling back to it in tests.
+  if ("${CMAKE_SYSTEM_NAME}" STREQUAL "Linux" AND NOT ANDROID AND ${arch} MATCHES "arm")
+    set(ASAN_TEST_TARGET_CFLAGS "${ASAN_TEST_TARGET_CFLAGS} -funwind-tables")
+  endif()
 endforeach()
 
 # iOS and iOS simulator test suites
 # These are not added into "check-all", in order to run these tests, use
 # "check-asan-iossim-x86_64" and similar. They also require that an extra env
 # variable to select which iOS device or simulator to use, e.g.:
 # SANITIZER_IOSSIM_TEST_DEVICE_IDENTIFIER="iPhone 6"
 if(APPLE)