[CALCITE-6580] Remove Locale.setDefault

* Remove its usage in tests where possible
* Needed for a few tests that are testing locale translations
* If a test uses Locale.setDefault, then it is isolated to avoid affecting other tests

babel/src/test/java/org/apache/calcite/test/BabelQuidemTest.java

@@ -41,7 +41,6 @@
 import net.hydromatic.quidem.Quidem;
 
 import org.checkerframework.checker.nullness.qual.Nullable;
-import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 
 import java.sql.Connection;
@@ -70,18 +69,10 @@ public static void main(String[] args) throws Exception {
     }
   }
 
-  private Locale originalLocale;
-
   @BeforeEach public void setup() {
-    originalLocale = Locale.getDefault();
-    Locale.setDefault(Locale.US);
     MaterializationService.setThreadLocal();
   }
 
-  @AfterEach public void cleanup() {
-    Locale.setDefault(originalLocale);
-  }
-
   /** For {@link QuidemTest#test(String)} parameters. */
   @Override public Collection<String> getPath() {
     // Start with a test file we know exists, then find the directory and list