[lldb][yaml2macho-core] change the two API tests to skipUnlessDarwin

These two 32-bit macho corefile tests are still failing on the
lldb-remote-linux-win bot, I'd expect the @skipIfWindows decorator
to skip the tests there until I can debug this, but somehow because
it's a remote windows execution it's not working.  Change these tests
back to skipUnlessDarwin until I can figure out whether it's
yaml2macho-core or lldb's 32-bit mach-o corefile reader support on
windows which is the problem.

Author: jasonmolenda

lldb/test/API/macosx/arm-corefile-regctx/TestArmMachoCorefileRegctx.py

@@ -13,7 +13,7 @@
 class TestArmMachoCorefileRegctx(TestBase):
     NO_DEBUG_INFO_TESTCASE = True
 
-    @skipIfWindows # CI fail on Windows, lr has value 0x0F000000?
+    @skipUnlessDarwin # CI fail on Windows, lr has value 0x0F000000?
     def test_armv7_corefile(self):
         ### Create corefile
         corefile = self.getBuildArtifact("core")

lldb/test/API/macosx/riscv32-corefile/TestRV32MachOCorefile.py

@@ -13,7 +13,7 @@
 class TestRV32MachOCorefile(TestBase):
     NO_DEBUG_INFO_TESTCASE = True
 
-    @skipIfWindows  # windows CI failure, says only 1 thread in corefile
+    @skipunlessDarwin  # windows CI failure, says only 1 thread in corefile
     @no_debug_info_test
     def test_riscv32_gpr_corefile_registers(self):
         corefile = self.getBuildArtifact("core")