Fix size of integer used in mysql testsuite

[Pavel Zhukov]

If mysql-devel installed but mysql-server is not build failed with:

test_284.adb:151:52: warning: value not in range of type "Num" defined at league-holders-generic_integers.ads:49, instance at league-holders-long_integers.ads:46
test_284.adb:151:52: warning: "Constraint_Error" will be raised at run time
test_284.adb:154:52: warning: value not in range of type "Num" defined at league-holders-generic_integers.ads:49, instance at league-holders-long_integers.ads:46
test_284.adb:154:52: warning: "Constraint_Error" will be raised at run time
test_284.adb:206:18: value not in range of type "Standard.Long_Integer"
test_284.adb:206:18: static expression fails Constraint_Check
test_284.adb:212:18: value not in range of type "Standard.Long_Integer"
test_284.adb:212:18: static expression fails Constraint_Check
compilation of test_284.adb failed
gprbuild: * compilation phase failed
make[1]: Leaving directory `'
make: Leaving directory `'
make[1]: * [mysql] Error 4
make: * [check] Error 2

[vadim.godunko]

In 4353:

New package to store Long_Long_Integer values in holders.

Refs #336.

[vadim.godunko]

In 4354:

Use Long_Long_Integer to handle 64-bit values. This is needed because
32-bit version of GNAT uses 32-bit integer for Long_Integer.

Refs #336.

[vadim.godunko]

In 4355:

Redefine types for storage members to be independend from platform.

Refs #336.

[vadim.godunko]

In 4356:

Explicitly specify character set to avoid failure when server's
character set is not UTF-8 (or someone another with cyrillic character
support).

Refs #336.