[fix](Nereids) fix cast string to date (#46065)

### What problem does this PR solve?

Issue Number: close #xxx

Related PR: #35637 

Problem Summary:
When cast("201-01-01" as datetimev2(0)), The result is "2020-01-01" but
it is wrong. It should be result in "0201-01-01".
201 would be regarded as 20xy-0z as related pr show, it was a bug. But
actually it should not have this trasformation and result in

fe/fe-core/src/main/java/org/apache/doris/nereids/rules/expression/rules/FoldConstantRuleOnFE.java

@@ -481,7 +481,7 @@ public Expression visitCast(Cast cast, ExpressionRewriteContext context) {
                 return ((DateLikeType) dataType).fromString(((StringLikeLiteral) child).getStringValue());
             } catch (AnalysisException t) {
                 if (cast.isExplicitType()) {
-                    return new NullLiteral(dataType);
+                    return cast;
                 } else {
                     // If cast is from type coercion, we don't use NULL literal and will throw exception.
                     throw t;

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/literal/DateLiteral.java

@@ -189,19 +189,23 @@ static Result<String, AnalysisException> normalize(String s) {
                 if (len == 4 || len == 2) {
                     sb.append(s, i, j);
                 } else if (len == 3) {
-                    if (partNumber == 0) {
-                        String yy = s.substring(i, i + 2);
-                        int year = Integer.parseInt(yy);
-                        if (year >= 0 && year <= 69) {
-                            sb.append("20");
-                        } else if (year >= 70 && year <= 99) {
-                            sb.append("19");
+                    if (s.charAt(j) == '.') {
+                        if (partNumber == 0) {
+                            String yy = s.substring(i, i + 2);
+                            int year = Integer.parseInt(yy);
+                            if (year >= 0 && year <= 69) {
+                                sb.append("20");
+                            } else if (year >= 70 && year <= 99) {
+                                sb.append("19");
+                            }
+                            sb.append(yy).append('-');
+                        } else {
+                            sb.append(s, i, i + 2).append(' ');
                         }
-                        sb.append(yy).append('-');
+                        j = j - 1;
                     } else {
-                        sb.append(s, i, i + 2).append(' ');
+                        sb.append("0").append(s, i, j);
                     }
-                    j = j - 1;
                 } else if (len == 1) {
                     if (partNumber == 0) {
                         sb.append("000").append(c);

regression-test/data/correctness_p0/test_cast_date_decimal.out

@@ -20,3 +20,6 @@ true
 -- !sql7 --
 \N	\N	\N	\N
 
+-- !sql8 --
+2012-03-12T03:00	0123-01-01T00:00	2012-03-12T12:23:59
+

regression-test/data/nereids_p0/sql_functions/cast_function/test_cast_function.out

@@ -6,7 +6,7 @@
 11
 
 -- !sql --
-\N
+2000-01-01T03:14:17
 
 -- !sql --
 \N

regression-test/data/query_p0/sql_functions/cast_function/test_cast_function.out

@@ -6,7 +6,7 @@
 11
 
 -- !sql --
-\N
+2000-01-01T03:14:17
 
 -- !sql --
 \N

regression-test/suites/correctness_p0/test_cast_date_decimal.groovy

@@ -43,4 +43,8 @@ suite("test_cast_date_decimal") {
     qt_sql7 """
         select /*+SET_VAR(debug_skip_fold_constant=true)*/ cast('0000-02-29' as date), cast('0000-02-29' as datetime), cast('00000229' as date), cast('0000-02-29 12:12:12.123' as datetime);
     """
+
+    qt_sql8 """
+        select cast('123.123' as datetimev2), cast('123-01-01' as datetimev2), cast('123.1212.235959' as datetimev2);
+    """
 }