disable non-unicode case insensitive trie matching

disable non-unicode case insensitive trie matching

Also revert 8902bb05b18c9858efa90229ca1ee42b17277554 as it merely
masked one symptom of the deeper problems.

Also fixes RT #69973, which was a segfault which was exposed by
8902bb05, see the ticket for further details.

http://rt.perl.org/rt3//Public/Bug/Display.html?id=69973

At the code of this is the problem that in unicode matching a bunch
of code points have case folding rules beyond just A-Z/a-z. Since
the case folding rules are decided at runtime by the string, we cant
use the same TRIE tables for both unicode/non-unicode matching.

Until this is reconciled or some other solution is found case insensitive
matching only gets the TRIE optimisation when the pattern is uniocde.

From CaseFolding.txt:

00B5; C; 03BC; # MICRO SIGN
00C0; C; 00E0; # LATIN CAPITAL LETTER A WITH GRAVE
00C1; C; 00E1; # LATIN CAPITAL LETTER A WITH ACUTE
00C2; C; 00E2; # LATIN CAPITAL LETTER A WITH CIRCUMFLEX
00C3; C; 00E3; # LATIN CAPITAL LETTER A WITH TILDE
00C4; C; 00E4; # LATIN CAPITAL LETTER A WITH DIAERESIS
00C5; C; 00E5; # LATIN CAPITAL LETTER A WITH RING ABOVE
00C6; C; 00E6; # LATIN CAPITAL LETTER AE
00C7; C; 00E7; # LATIN CAPITAL LETTER C WITH CEDILLA
00C8; C; 00E8; # LATIN CAPITAL LETTER E WITH GRAVE
00C9; C; 00E9; # LATIN CAPITAL LETTER E WITH ACUTE
00CA; C; 00EA; # LATIN CAPITAL LETTER E WITH CIRCUMFLEX
00CB; C; 00EB; # LATIN CAPITAL LETTER E WITH DIAERESIS
00CC; C; 00EC; # LATIN CAPITAL LETTER I WITH GRAVE
00CD; C; 00ED; # LATIN CAPITAL LETTER I WITH ACUTE
00CE; C; 00EE; # LATIN CAPITAL LETTER I WITH CIRCUMFLEX
00CF; C; 00EF; # LATIN CAPITAL LETTER I WITH DIAERESIS
00D0; C; 00F0; # LATIN CAPITAL LETTER ETH
00D1; C; 00F1; # LATIN CAPITAL LETTER N WITH TILDE
00D2; C; 00F2; # LATIN CAPITAL LETTER O WITH GRAVE
00D3; C; 00F3; # LATIN CAPITAL LETTER O WITH ACUTE
00D4; C; 00F4; # LATIN CAPITAL LETTER O WITH CIRCUMFLEX
00D5; C; 00F5; # LATIN CAPITAL LETTER O WITH TILDE
00D6; C; 00F6; # LATIN CAPITAL LETTER O WITH DIAERESIS
00D8; C; 00F8; # LATIN CAPITAL LETTER O WITH STROKE
00D9; C; 00F9; # LATIN CAPITAL LETTER U WITH GRAVE
00DA; C; 00FA; # LATIN CAPITAL LETTER U WITH ACUTE
00DB; C; 00FB; # LATIN CAPITAL LETTER U WITH CIRCUMFLEX
00DC; C; 00FC; # LATIN CAPITAL LETTER U WITH DIAERESIS
00DD; C; 00FD; # LATIN CAPITAL LETTER Y WITH ACUTE
00DE; C; 00FE; # LATIN CAPITAL LETTER THORN
00DF; F; 0073 0073; # LATIN SMALL LETTER SHARP S