[lldb][test] Diable dwp hash collision test on Windows

This has been flaky on our Windows on Arm bot:
https://lab.llvm.org/buildbot/#/builders/141/builds/1497

Despite passing when first landed.

Author: DavidSpickett

lldb/test/Shell/SymbolFile/DWARF/x86/dwp-hash-collision.s

@@ -3,6 +3,9 @@
 ## split unit from the DWP file. This can sometimes happen when the compile unit
 ## is nearly empty (e.g. because LTO has optimized all of it away).
 
+# Is flaky on Windows on Arm.
+# UNSUPPORTED: system-windows
+
 # RUN: llvm-mc -triple=x86_64-pc-linux -filetype=obj %s --defsym MAIN=0 > %t
 # RUN: llvm-mc -triple=x86_64-pc-linux -filetype=obj %s > %t.dwp
 # RUN: %lldb %t -o "image lookup -t my_enum_type" \