test: correct flags for Windows

Adjust the flags for the LLDB test on Windows.  This test was previously
not running, but after the fix to the python detection, we now run this.

Author: compnerd

lldb/packages/Python/lldbsuite/test/functionalities/dead-strip/Makefile

@@ -6,6 +6,8 @@ endif
 
 ifeq "$(OS)" "Darwin"
     LD_EXTRAS = -Xlinker -dead_strip
+else ifeq "$(OS)" "Windows_NT"
+    CFLAGS_EXTRAS += /Gw /Gy
 else
     CFLAGS_EXTRAS += -fdata-sections -ffunction-sections
     LD_EXTRAS = -Wl,--gc-sections