SNOW-1857250: More fixes to AST generation in functions.py (#2793)

1. Which Jira issue is this PR addressing? Make sure that there is an
accompanying issue to your PR.

   Fixes SNOW-1857250

2. Fill out the following pre-review checklist:

- [ ] I am adding a new automated test(s) to verify correctness of my
new code
- [ ] If this test skips Local Testing mode, I'm requesting review from
@snowflakedb/local-testing
   - [ ] I am adding new logging messages
   - [ ] I am adding a new telemetry message
   - [ ] I am adding new credentials
   - [ ] I am adding a new dependency
- [ ] If this is a new feature/behavior, I'm adding the Local Testing
parity changes.
- [x] I acknowledge that I have ensured my changes to be thread-safe.
Follow the link for more information: [Thread-safe Developer
Guidelines](https://github.com/snowflakedb/snowpark-python/blob/main/CONTRIBUTING.md#thread-safe-development)

3. Please describe how your code solves the related issue.

Fixed the AST generation where columns where recorded as literals
instead of column parameters and parameters were being rearranged in
some cases.
This change gets rid of a lot of unnecessary `col()` in the unparsed
code; this helps match the unparser code with the original code.

Author: sfc-gh-vbudati

src/snowflake/snowpark/functions.py

@@ -753,17 +753,31 @@ def convert_timezone(
     )
     target_tz = _to_col_if_str(target_timezone, "convert_timezone")
     source_time_to_convert = _to_col_if_str(source_time, "convert_timezone")
-
+    # Build AST here to prevent rearrangement of args in the encoded AST.
+    ast = (
+        build_function_expr(
+            "convert_timezone",
+            [target_timezone, source_time, source_timezone],
+            ignore_null_args=True,
+        )
+        if _emit_ast
+        else None
+    )
     if source_timezone is None:
         return call_builtin(
-            "convert_timezone", target_tz, source_time_to_convert, _emit_ast=_emit_ast
+            "convert_timezone",
+            target_tz,
+            source_time_to_convert,
+            _ast=ast,
+            _emit_ast=False,
         )
     return call_builtin(
         "convert_timezone",
         source_tz,
         target_tz,
         source_time_to_convert,
-        _emit_ast=_emit_ast,
+        _ast=ast,
+        _emit_ast=False,
     )
 
 
@@ -889,7 +903,7 @@ def count_distinct(*cols: ColumnOrName, _emit_ast: bool = True) -> Column:
     return Column(
         FunctionExpression("count", [c._expression for c in cs], is_distinct=True),
         _ast=ast,
-        _emit_ast=_emit_ast,
+        _emit_ast=False,
     )
 
 
@@ -4331,7 +4345,12 @@ def next_day(
         [Row(NEXT_DAY("A", 'FR')=datetime.date(2020, 8, 7)), Row(NEXT_DAY("A", 'FR')=datetime.date(2020, 12, 4))]
     """
     c = _to_col_if_str(date, "next_day")
-    return builtin("next_day", _emit_ast=_emit_ast)(c, Column._to_expr(day_of_week))
+    # Build AST here to prevent `date` from being recorded as a Column instead of a literal and
+    # `day_of_week` from being recorded as a literal instead of Column.
+    ast = build_function_expr("next_day", [date, day_of_week]) if _emit_ast else None
+    return builtin("next_day", _ast=ast, _emit_ast=False)(
+        c, Column._to_expr(day_of_week)
+    )
 
 
 @publicapi
@@ -4354,7 +4373,14 @@ def previous_day(
         [Row(PREVIOUS_DAY("A", 'FR')=datetime.date(2020, 7, 31)), Row(PREVIOUS_DAY("A", 'FR')=datetime.date(2020, 11, 27))]
     """
     c = _to_col_if_str(date, "previous_day")
-    return builtin("previous_day", _emit_ast=_emit_ast)(c, Column._to_expr(day_of_week))
+    # Build AST here to prevent `date` from being recorded as a Column instead of a literal and
+    # `day_of_week` from being recorded as a literal instead of Column.
+    ast = (
+        build_function_expr("previous_day", [date, day_of_week]) if _emit_ast else None
+    )
+    return builtin("previous_day", _ast=ast, _emit_ast=False)(
+        c, Column._to_expr(day_of_week)
+    )
 
 
 @publicapi