[feature](function)Support function "current_date" in FE (#11702)

Issue Number: close #11699

fe/fe-core/src/main/java/org/apache/doris/rewrite/FEFunctions.java

@@ -255,6 +255,11 @@ public class FEFunctions {
                 ScalarType.getDefaultDateType(Type.DATE));
     }
 
+    @FEFunction(name = "current_date", argTypes = {}, returnType = "DATE")
+    public static DateLiteral currentDate() {
+        return curDate();
+    }
+
     @FEFunction(name = "curtime", argTypes = {}, returnType = "TIME")
     public static FloatLiteral curTime() throws AnalysisException {
         DateLiteral now = now();

fe/fe-core/src/test/java/org/apache/doris/planner/ConstantExpressTest.java

@@ -122,6 +122,10 @@ public class ConstantExpressTest {
         testConstantExpressResult(
                 "select current_time();",
                 "");
+
+        testConstantExpressResult(
+                "select current_date();",
+                "");
     }
 
     @Test