[lldb][test] TestProcessSaveCoreMinidump: Rename duplicate test-case (#148600)

Ran my python script from
#97043 over the repo again and
there was 1 duplicate test-case that has been introduced since I last
did this.

This patch renames that test.

Author: Michael137

lldb/test/API/functionalities/process_save_core_minidump/TestProcessSaveCoreMinidump.py

@@ -608,7 +608,7 @@ def minidump_deterministic_difference(self):
 
     @skipUnlessPlatform(["linux"])
     @skipUnlessArch("x86_64")
-    def minidump_saves_fs_base_region(self):
+    def minidump_saves_tls(self):
         self.build()
         exe = self.getBuildArtifact("a.out")
         try: