update tests, add decoder functionality for dataframe.write.test, dataframe.count2.test, fixed col_in decoder

Author: sfc-gh-vbudati

tests/ast/data/DataFrame.count2.test

@@ -37,26 +37,28 @@ body {
           sp_dataframe_schema__struct {
             v {
               fields {
-                column_identifier {
-                  name: "\"A\""
-                }
-                data_type {
-                  sp_string_type {
-                    length {
-                      value: 16777216
+                list {
+                  column_identifier {
+                    name: "\"A\""
+                  }
+                  data_type {
+                    sp_string_type {
+                      length {
+                        value: 16777216
+                      }
                     }
                   }
+                  nullable: true
                 }
-                nullable: true
-              }
-              fields {
-                column_identifier {
-                  name: "\"B\""
-                }
-                data_type {
-                  sp_long_type: true
+                list {
+                  column_identifier {
+                    name: "\"B\""
+                  }
+                  data_type {
+                    sp_long_type: true
+                  }
+                  nullable: true
                 }
-                nullable: true
               }
             }
           }

tests/ast/data/Dataframe.to_snowpark_pandas.test

@@ -37,10 +37,7 @@ body {
           }
         }
         src {
-          end_column: 41
-          end_line: 25
           file: "SRC_POSITION_TEST_MODE"
-          start_column: 13
           start_line: 25
         }
         variant {
@@ -69,10 +66,7 @@ body {
           }
         }
         src {
-          end_column: 52
-          end_line: 27
           file: "SRC_POSITION_TEST_MODE"
-          start_column: 29
           start_line: 27
         }
       }
@@ -101,10 +95,7 @@ body {
           list: "A"
         }
         src {
-          end_column: 65
-          end_line: 29
           file: "SRC_POSITION_TEST_MODE"
-          start_column: 29
           start_line: 29
         }
       }
@@ -134,10 +125,7 @@ body {
           }
         }
         src {
-          end_column: 70
-          end_line: 31
           file: "SRC_POSITION_TEST_MODE"
-          start_column: 29
           start_line: 31
         }
       }
@@ -170,10 +158,7 @@ body {
           list: "A"
         }
         src {
-          end_column: 87
-          end_line: 33
           file: "SRC_POSITION_TEST_MODE"
-          start_column: 29
           start_line: 33
         }
       }

tests/ast/data/Table.merge.test

@@ -165,25 +165,27 @@ body {
           sp_dataframe_schema__struct {
             v {
               fields {
-                column_identifier {
-                  name: "num"
-                }
-                data_type {
-                  sp_integer_type: true
-                }
-                nullable: true
-              }
-              fields {
-                column_identifier {
-                  name: "str"
+                list {
+                  column_identifier {
+                    name: "num"
+                  }
+                  data_type {
+                    sp_integer_type: true
+                  }
+                  nullable: true
                 }
-                data_type {
-                  sp_string_type {
-                    length {
+                list {
+                  column_identifier {
+                    name: "str"
+                  }
+                  data_type {
+                    sp_string_type {
+                      length {
+                      }
                     }
                   }
+                  nullable: true
                 }
-                nullable: true
               }
             }
           }