strptime: Support some of abbriviated timezone strings for GNU extensions

[cosmo0920]

I implemented a capability to process TimeZone strings.
Plus, FLB_HAVE_ZONE is currently nothing effective. This is a vestigial macro that was used or copied from the original BSD's strptime.c code.
Instead, we're able to use a detector which tries to compile the tm_zone member existence in struct tm to enable the conditional macro for tm_zone.
Also, I added basic scenarios to run assertions for time zone strings and other functionalities on flb_strptime.

The corresponding issue is: #10331

This is because internally, we use flb_strptime as a time format parser on flb_parser.c.
So, this change is effective for fluent-bit's parser.

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The current supported time zone labels of 3-4 letter abbreviated strings:

Supported Timezone Abbreviations

UTC/GMT and Zulu

Abbreviation	UTC Offset (HH:MM)	Offset (Seconds)	Is DST	Description
GMT	+00:00	0	0	Greenwich Mean Time
UTC	+00:00	0	0	Coordinated Universal Time
Z	+00:00	0	0	Zulu Time (UTC)
UT	+00:00	0	0	Universal Time

North American Timezones

Abbreviation	UTC Offset (HH:MM)	Offset (Seconds)	Is DST	Description
EST	-05:00	-18000	0	Eastern Standard Time
EDT	-04:00	-14400	1	Eastern Daylight Time
CST	-06:00	-21600	0	Central Standard Time (North America)
CDT	-05:00	-18000	1	Central Daylight Time (North America)
MST	-07:00	-25200	0	Mountain Standard Time
MDT	-06:00	-21600	1	Mountain Daylight Time
PST	-08:00	-28800	0	Pacific Standard Time
PDT	-07:00	-25200	1	Pacific Daylight Time
AKST	-09:00	-32400	0	Alaska Standard Time
AKDT	-08:00	-28800	1	Alaska Daylight Time
HST	-10:00	-36000	0	Hawaii Standard Time
HADT	-09:00	-32400	1	Hawaii-Aleutian Daylight Time (rarely used for Hawaii)
AST	-04:00	-14400	0	Atlantic Standard Time (e.g., Canada, Caribbean)
ADT	-03:00	-10800	1	Atlantic Daylight Time
NST	-03:30	-12600	0	Newfoundland Standard Time
NDT	-02:30	-9000	1	Newfoundland Daylight Time

European Timezones

Abbreviation	UTC Offset (HH:MM)	Offset (Seconds)	Is DST	Description
WET	+00:00	0	0	Western European Time
WEST	+01:00	3600	1	Western European Summer Time
CET	+01:00	3600	0	Central European Time
CEST	+02:00	7200	1	Central European Summer Time
EET	+02:00	7200	0	Eastern European Time
EEST	+03:00	10800	1	Eastern European Summer Time
MSK	+03:00	10800	0	Moscow Standard Time

South American Timezones

Abbreviation	UTC Offset (HH:MM)	Offset (Seconds)	Is DST	Description
ART	-03:00	-10800	0	Argentina Time
BRT	-03:00	-10800	0	Brazil Time (main population areas, can vary by region/DST)
BRST	-02:00	-7200	1	Brazil Summer Time (historical, not currently observed by all)
CLT	-04:00	-14400	0	Chile Standard Time
CLST	-03:00	-10800	1	Chile Summer Time

Australasian / Oceanian Timezones

Abbreviation	UTC Offset (HH:MM)	Offset (Seconds)	Is DST	Description
AEST	+10:00	36000	0	Australian Eastern Standard Time
AEDT	+11:00	39600	1	Australian Eastern Daylight Time
ACST	+09:30	34200	0	Australian Central Standard Time
ACDT	+10:30	37800	1	Australian Central Daylight Time
AWST	+08:00	28800	0	Australian Western Standard Time
NZST	+12:00	43200	0	New Zealand Standard Time
NZDT	+13:00	46800	1	New Zealand Daylight Time

Asian Timezones

Abbreviation	UTC Offset (HH:MM)	Offset (Seconds)	Is DST	Description
JST	+09:00	32400	0	Japan Standard Time
KST	+09:00	32400	0	Korea Standard Time
SGT	+08:00	28800	0	Singapore Time
IST	+05:30	19800	0	India Standard Time
GST	+04:00	14400	0	Gulf Standard Time (e.g., UAE, Oman)
ICT	+07:00	25200	0	Indochina Time (Thailand, Vietnam, Laos, Cambodia)
WIB	+07:00	25200	0	Western Indonesian Time
WITA	+08:00	28800	0	Central Indonesian Time
WIT	+09:00	32400	0	Eastern Indonesian Time
MYT	+08:00	28800	0	Malaysia Time
BDT	+06:00	21600	0	Bangladesh Standard Time
NPT	+05:45	20700	0	Nepal Time

African Timezones

Abbreviation	UTC Offset (HH:MM)	Offset (Seconds)	Is DST	Description
WAT	+01:00	3600	0	West Africa Time
CAT	+02:00	7200	0	Central Africa Time
EAT	+03:00	10800	0	East Africa Time
SAST	+02:00	7200	0	South Africa Standard Time

Military Timezones

These are single-letter UTC offset designators. 'J' (Juliett) represents local time and is not included. 'Z' (Zulu) is UTC and listed above.

Abbreviation	UTC Offset (HH:MM)	Offset (Seconds)	Is DST	Description
A	+01:00	3600	0	Alpha Time Zone
B	+02:00	7200	0	Bravo Time Zone
C	+03:00	10800	0	Charlie Time Zone
D	+04:00	14400	0	Delta Time Zone
E	+05:00	18000	0	Echo Time Zone
F	+06:00	21600	0	Foxtrot Time Zone
G	+07:00	25200	0	Golf Time Zone
H	+08:00	28800	0	Hotel Time Zone
I	+09:00	32400	0	India Time Zone (Military, not India Standard Time)
K	+10:00	36000	0	Kilo Time Zone
L	+11:00	39600	0	Lima Time Zone
M	+12:00	43200	0	Mike Time Zone
N	-01:00	-3600	0	November Time Zone
O	-02:00	-7200	0	Oscar Time Zone
P	-03:00	-10800	0	Papa Time Zone
Q	-04:00	-14400	0	Quebec Time Zone
R	-05:00	-18000	0	Romeo Time Zone
S	-06:00	-21600	0	Sierra Time Zone
T	-07:00	-25200	0	Tango Time Zone
U	-08:00	-28800	0	Uniform Time Zone
V	-09:00	-32400	0	Victor Time Zone
W	-10:00	-36000	0	Whiskey Time Zone
X	-11:00	-43200	0	X-ray Time Zone
Y	-12:00	-46800	0	Yankee Time Zone

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