Add extension requirement

Author: luciechoi

test/Feature/MaximalReconvergence/loop_peeling.test

@@ -34,6 +34,10 @@ DescriptorSets:
 ...
 
 #--- end
+# UNSUPPORTED: !VK_KHR_shader_maximal_reconvergence
+
+# BUG: https://github.com/llvm/llvm-project/issues/164496
+# XFAIL: Clang && Vulkan
 
 # RUN: split-file %s %t
 # RUN: %dxc_target -T cs_6_5 -fspv-enable-maximal-reconvergence -Fo %t.o %t/source.hlsl

test/Feature/MaximalReconvergence/subgroup_uniform_control_flow.test

@@ -42,6 +42,7 @@ DescriptorSets:
 ...
 
 #--- end
+# UNSUPPORTED: Vulkan && !VK_KHR_shader_maximal_reconvergence
 
 # RUN: split-file %s %t
 # RUN: %dxc_target -T cs_6_0 -fspv-enable-maximal-reconvergence -Fo %t.o %t/source.hlsl