[compiler-rt] Mark symbolize_stack_fp test unsupported on Arm Thumb

The new test `symbolize_stack_fp.cpp` added in
https://reviews.llvm.org/D102046 assumes that
we can fall back to the fast unwinder.

This is not the case for Thumb and the test is currently
failing on our v7 thumb bot:
https://lab.llvm.org/buildbot/#/builders/26/builds/2096

Skip the test if we're building for a Thumb target.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D103512

compiler-rt/test/sanitizer_common/TestCases/Linux/symbolize_stack_fp.cpp

@@ -7,6 +7,9 @@
 // On android %t is a wrapper python script so llvm-readelf will fail.
 // UNSUPPORTED: android
 
+/// Fast unwinder does not work with Thumb code
+// UNSUPPORTED: thumb
+
 /// No .eh_frame && -g => .debug_frame
 // SEC: .debug_frame
 

compiler-rt/test/sanitizer_common/lit.common.cfg.py

@@ -31,6 +31,9 @@ config.available_features.add(config.tool_name)
 if config.host_os == 'Linux' and config.tool_name == "lsan" and config.target_arch == 'i386':
   config.available_features.add("lsan-x86")
 
+if config.arm_thumb:
+  config.available_features.add('thumb')
+
 if config.host_os == 'Darwin':
   # On Darwin, we default to `abort_on_error=1`, which would make tests run
   # much slower. Let's override this and run lit tests with 'abort_on_error=0'.

compiler-rt/test/sanitizer_common/lit.site.cfg.py.in

@@ -6,6 +6,8 @@ config.tool_name = "@SANITIZER_COMMON_LIT_TEST_MODE@"
 config.target_cflags = "@SANITIZER_COMMON_TEST_TARGET_CFLAGS@"
 config.target_arch = "@SANITIZER_COMMON_TEST_TARGET_ARCH@"
 
+config.arm_thumb = "@COMPILER_RT_ARM_THUMB@"
+
 # Load common config for all compiler-rt lit tests.
 lit_config.load_config(config, "@COMPILER_RT_BINARY_DIR@/test/lit.common.configured")