[lldb] Remove all remaining tabs from TestReturnValue.py

I assumed this was just a single typo, but it seems we actually have
a whole bunch of tabs in this file which cause Python to complain
about mixing tabs and spaces.

Author: Teemperor

lldb/packages/Python/lldbsuite/test/functionalities/return-value/TestReturnValue.py

@@ -127,7 +127,7 @@ def test_with_python(self):
         #self.assertTrue(in_float == return_float)
 
         if not self.affected_by_radar_34562999() and not self.affected_by_pr44132():
-	    self.return_and_test_struct_value("return_one_int")
+            self.return_and_test_struct_value("return_one_int")
             self.return_and_test_struct_value("return_two_int")
             self.return_and_test_struct_value("return_three_int")
             self.return_and_test_struct_value("return_four_int")
@@ -185,12 +185,12 @@ def test_vector_values(self):
 
         self.return_and_test_struct_value("return_vector_size_float32_8")
         self.return_and_test_struct_value("return_vector_size_float32_16")
-	if not self.affected_by_pr44132():
-		self.return_and_test_struct_value("return_vector_size_float32_32")
+        if not self.affected_by_pr44132():
+            self.return_and_test_struct_value("return_vector_size_float32_32")
         self.return_and_test_struct_value("return_ext_vector_size_float32_2")
         self.return_and_test_struct_value("return_ext_vector_size_float32_4")
-	if not self.affected_by_pr44132():
-		self.return_and_test_struct_value("return_ext_vector_size_float32_8")
+        if not self.affected_by_pr44132():
+            self.return_and_test_struct_value("return_ext_vector_size_float32_8")
 
     # limit the nested struct and class tests to only x86_64
     @skipIf(archs=no_match(['x86_64']))