Always pick the correct argument in gen_or().

I got the comments right, but not all of the code, fix that and update
the tests.

Author: infrastation

gencode.c

@@ -1462,10 +1462,10 @@ gen_or(struct block *b0, struct block *b1)
 		return b0;
 	// True or X is true.
 	if (b0->meaning == IS_TRUE)
-		return b1;
+		return b0;
 	// X or true is true.
 	if (b1->meaning == IS_TRUE)
-		return b0;
+		return b1;
 
 	// b0->meaning == IS_UNCERTAIN && b1->meaning == IS_UNCERTAIN
 	b0->sense = !b0->sense;

testprogs/TESTrun

@@ -17265,7 +17265,9 @@ my @accept_blocks = (
 			'ip6 or ip',      #  [3] False     or  true      is true.
 			'not ip or ip',   #  [3] Not true  or  true      is true.
 			'ip or ip',       #  [4] True      or  true      is true.
-			'not ip6 or ip',  #  [4] Not false or  true      is not false. (BUG!)
+			'ip or not ip6',  #  [4] True      or  not false is true.
+			'ip or igmp',     #  [9] True      or  X         is true.
+			'igmp or ip',     # [10] X         or  true      is true.
 		],
 		opt => '
 			(000) ret      #262144
@@ -17289,8 +17291,10 @@ my @accept_blocks = (
 			'not ip6 or not ip',   #  [2] Not false or  not true  is not false.
 			'ip6 or not ip6',      #  [3] False     or  not false is not false.
 			'not ip or not ip6',   #  [3] Not true  or  not false is not false.
+			'not ip6 or ip',       #  [4] Not false or  true      is not false.
 			'not ip6 or not ip6',  #  [4] Not false or  not false is not false.
-			'ip or not ip6',       #  [4] True      or  not false is true.      (BUG!)
+			'not ip6 or igmp',     #  [9] Not false or  X         is not false.
+			'igmp or not ip6',     # [10] X         or  not false is not false.
 		],
 		opt => '
 			(000) ret      #262144
@@ -17316,10 +17320,6 @@ my @accept_blocks = (
 			'not ip or igmp',   #  [7] Not true  or  X         is X.
 			'igmp or ip6',      #  [8] X         or  false     is X.
 			'igmp or not ip',   #  [8] X         or  not true  is X.
-			'ip or igmp',       #  [9] True      or  X         is true.      (BUG!)
-			'not ip6 or igmp',  #  [9] Not false or  X         is not false. (BUG!)
-			'igmp or ip',       # [10] X         or  true      is true.      (BUG!)
-			'igmp or not ip6',  # [10] X         or  not false is not false. (BUG!)
 		],
 		optunopt => '
 			(000) ldb      [9]