Fixed bug#30059.

Server handles truncation for assignment of too-long values
into CHAR/VARCHAR/TEXT columns in a different ways when the
truncated characters are spaces:
1. CHAR(N) columns silently ignore end-space truncation;
2. TEXT columns post a truncation warning/error in the
   non-strict/strict mode.
3. VARCHAR columns always post a truncation note in
   any mode.

Space truncation processing has been synchronised over
CHAR/VARCHAR/TEXT columns: current behavior of VARCHAR
columns has been propagated as standard.

Binary-encoded string/BLOB columns are not affected.


mysql-test/r/heap.result:
  Updated test case for bug#30059.
mysql-test/r/innodb.result:
  Updated test case for bug#30059.
mysql-test/r/myisam.result:
  Updated test case for bug#30059.
mysql-test/r/strict.result:
  Updated test case for bug#30059.
mysql-test/r/type_binary.result:
  Updated test case for bug#30059.
mysql-test/r/warnings.result:
  Added test case for bug#30059.
mysql-test/t/warnings.test:
  Added test case for bug#30059.
sql/field.cc:
  Fixed bug#30059.
  The report_data_too_long function was replaced with the
  Field_longstr::report_if_important_data method.
  
  The Field_string::store and the Field_blob::store
  methods was synchronized with the Field_varstring::store
  method.
  Changes:
  1. to CHAR(N): posting of space truncation note has been added
     in both (strict and non-strict) modes;
  2. to BLOBs: a check for space truncation has been added,
     a warning in the non-strict mode and an error message in
     the strict mode have been replaced with a truncation note.
  
  Similar parts of Field_string::store, Field_blob::store and
  Field_varstring::store have been moved to the
  Field_longstr::report_if_important_data method.
sql/field.h:
  Fixed bug#30059.
  The Field_longstr::report_if_important_data method has been declared.

mysql-test/r/innodb.result

@@ -1901,6 +1901,7 @@ set @a=repeat(' ',20);
 insert into t1 values (concat('+',@a),concat('+',@a),concat('+',@a));
 Warnings:
 Note	1265	Data truncated for column 'v' at row 1
+Note	1265	Data truncated for column 'c' at row 1
 select concat('*',v,'*',c,'*',t,'*') from t1;
 concat('*',v,'*',c,'*',t,'*')
 *+ *+*+ *