Tonga switched to standard time in 1945, not 1901

(Thanks to Michael Deckers.)  Also, update its LMT before 1945,
and adjust geographical coordinates to match.
* NEWS: Mention this.
* australasia (Pacific/Tongatapu): Standard time adopted
1945-09-10, not 1901.  Subtract 8 seconds from LMT before that.
* zone.tab, zone1970.tab (Pacific/Tongatapu): Adjust coordinates
to match adjusted LMT.

NEWS

@@ -12,13 +12,14 @@ Unreleased, experimental changes
 	standard time in 1911, not 1915; and corrections to 1975 and
         1992 transitions
       - Portugal: DST was observed in 1950
-      - Tonga: moved from +12:20 to +13 in 1961, not 1941
+      - Tonga: adopted standard time in 1945 not 1901, and moved from
+        +12:20 to +13 in 1961 not 1941
     Additional fixes to entries in the 'backzone' file include:
       - Gambia: 1933 and 1942 transitions
       - Malawi: several 1911 through 1925 transitions
       - Sierra Leone: several 1913 through 1941 transitions, and DST
         was NOT observed in 1957 through 1962
-    (Thanks to Alois Treindl and P Chan.)
+    (Thanks to P Chan, Michael Deckers and Alois Treindl.)
 
   Changes to code
 

australasia

@@ -795,7 +795,7 @@ Rule	Tonga	2001	2002	-	Jan	lastSun	2:00	0	-
 Rule	Tonga	2016	only	-	Nov	Sun>=1	2:00	1:00	-
 Rule	Tonga	2017	only	-	Jan	Sun>=15	3:00	0	-
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
-Zone Pacific/Tongatapu	12:19:20 -	LMT	1901
+Zone Pacific/Tongatapu	12:19:12 -	LMT	1945 Sep 10
 			12:20	-	+1220	1961
 			13:00	-	+13	1999
 			13:00	Tonga	+13/+14
@@ -2021,6 +2021,17 @@ Zone	Pacific/Wallis	12:15:20 -	LMT	1901
 
 # Tonga
 
+# From Paul Eggert (2021-03-04):
+# In 1943 "The standard time kept is 12 hrs. 19 min. 12 sec. fast
+# on Greenwich mean time." according to the Admiralty's Hydrographic
+# Dept., Pacific Islands Pilot, Vol. II, 7th ed., 1943, p 360.
+
+# From Michael Deckers (2021-03-03):
+# [Ian R Bartky: "One Time Fits All: The Campaigns for Global Uniformity".
+# Stanford University Press. 2007. p 24..26]:
+# On 10 September 1945 Tonga adopted a standard time 12 hours,
+# 20 minutes in advance of Greenwich.
+
 # From Paul Eggert (1996-01-22):
 # Today's _Wall Street Journal_ (p 1) reports that "Tonga has been plotting
 # to sneak ahead of [New Zealanders] by introducing daylight-saving time."

zone.tab

@@ -391,7 +391,7 @@ TK	-0922-17114	Pacific/Fakaofo
 TL	-0833+12535	Asia/Dili
 TM	+3757+05823	Asia/Ashgabat
 TN	+3648+01011	Africa/Tunis
-TO	-2110-17510	Pacific/Tongatapu
+TO	-210800-1751200	Pacific/Tongatapu
 TR	+4101+02858	Europe/Istanbul
 TT	+1039-06131	America/Port_of_Spain
 TV	-0831+17913	Pacific/Funafuti

zone1970.tab

@@ -334,7 +334,7 @@ TK	-0922-17114	Pacific/Fakaofo
 TL	-0833+12535	Asia/Dili
 TM	+3757+05823	Asia/Ashgabat
 TN	+3648+01011	Africa/Tunis
-TO	-2110-17510	Pacific/Tongatapu
+TO	-210800-1751200	Pacific/Tongatapu
 TR	+4101+02858	Europe/Istanbul
 TT,AG,AI,BL,DM,GD,GP,KN,LC,MF,MS,VC,VG,VI	+1039-06131	America/Port_of_Spain
 TV	-0831+17913	Pacific/Funafuti