test(isthmus): remove redundant assertSame test in UnquotedCasingTest

Author: nielspardon

isthmus/src/test/java/io/substrait/isthmus/UnquotedCasingTest.java

@@ -1,7 +1,6 @@
 package io.substrait.isthmus;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertSame;
 
 import io.substrait.isthmus.sql.SubstraitCreateStatementParser;
 import io.substrait.plan.Plan;
@@ -41,12 +40,6 @@ void constructorCasingToLower() {
     assertEquals(Casing.TO_LOWER, provider.getUnquotedCasing());
   }
 
-  @Test
-  void getUnquotedCasingReturnsSameInstance() {
-    ConverterProvider provider = new ConverterProvider(Casing.UNCHANGED);
-    assertSame(Casing.UNCHANGED, provider.getUnquotedCasing());
-  }
-
   /**
    * With the default {@link Casing#TO_UPPER}, both CREATE TABLE and SELECT fold unquoted
    * identifiers to upper-case. The resulting {@link NamedScan} table name is {@code EMPLOYEES}.