HHH-18301 DB2 LUW supports DROP TABLE IF EXISTS since 11.5

Signed-off-by: Gavin King <gavin@hibernate.org>

hibernate-core/src/main/java/org/hibernate/dialect/DB2400Dialect.java

@@ -31,6 +31,11 @@ public class DB2400Dialect extends DB2Dialect {
 		return NoSequenceSupport.INSTANCE;
 	}
 
+	@Override
+	public boolean supportsIfExistsBeforeTableName() {
+		return false;
+	}
+
 	@Override
 	public String getQuerySequencesString() {
 		return null;

hibernate-core/src/main/java/org/hibernate/dialect/DB2Dialect.java

@@ -883,6 +883,11 @@ public class DB2Dialect extends Dialect {
 		return true;
 	}
 
+	@Override
+	public boolean supportsIfExistsBeforeTableName() {
+		return getVersion().isSameOrAfter( 11, 5 );
+	}
+
 	@Override
 	public SqmMultiTableMutationStrategy getFallbackSqmMutationStrategy(
 			EntityMappingType rootEntityDescriptor,

hibernate-core/src/main/java/org/hibernate/dialect/DB2iDialect.java

@@ -87,6 +87,11 @@ public class DB2iDialect extends DB2Dialect {
 		return "";
 	}
 
+	@Override
+	public boolean supportsIfExistsBeforeTableName() {
+		return false;
+	}
+
 	@Override
 	public boolean supportsDistinctFromPredicate() {
 		return true;

hibernate-core/src/main/java/org/hibernate/dialect/DB2zDialect.java

@@ -95,6 +95,11 @@ public class DB2zDialect extends DB2Dialect {
 		return DB2_LUW_VERSION;
 	}
 
+	@Override
+	public boolean supportsIfExistsBeforeTableName() {
+		return false;
+	}
+
 	@Override
 	public String getCreateIndexString(boolean unique) {
 		// we only create unique indexes, as opposed to unique constraints,