Fix the 'ouble' bug

[dc03]

Adding onto the commit message, here is the relevant state of the compiler when parsing the following code, where the ^ represents the variable pos in collect_variables() and code is printed before synt each time:

buf = buffer_create(32000, buffer_grow, 4);
local double i = 0.0;
local double j = 0.5;

FOUND LOCAL/GLOBAL KEYWORD:
{buf=buffer_create(32000,buffer_grow,4);localdoublei=0.0;localdoublej=0.5;};
{nnn=nnnnnnnnnnnnn(00000,nnnnnnnnnnn,0);LLLLLttttttn=000;LLLLLttttttn=000;};
                                        ^
Declared double i as local
WHILE DECLARING:
{buf=buffer_create(32000,buffer_grow,4);i=0.0;localdoublej=0.5;};
{nnn=nnnnnnnnnnnnn(00000,nnnnnnnnnnn,0);n=000;LLLLLttttttn=000;};
                                             ^
ERASE FROM CODE: i
dec_name: i
AFTER ERASING INIT:
{buf=buffer_create(32000,buffer_grow,4);i=0.0;localdoublej=0.5;};
{nnn=nnnnnnnnnnnnn(00000,nnnnnnnnnnn,0);n=000;LLLLLttttttn=000;};
                                              ^
FOUND LOCAL/GLOBAL KEYWORD:
{buf=buffer_create(32000,buffer_grow,4);i=0.0;localdoublej=0.5;};
{nnn=nnnnnnnnnnnnn(00000,nnnnnnnnnnn,0);n=000;LLLLLttttttn=000;};
                                               ^
Declared ouble j as local
WHILE DECLARING:
{buf=buffer_create(32000,buffer_grow,4);i=0.0;lj=0.5;};
{nnn=nnnnnnnnnnnnn(00000,nnnnnnnnnnn,0);n=000;Ln=000;};
                                                    ^
ERASE FROM CODE: j
dec_name: j
AFTER ERASING INIT:
{buf=buffer_create(32000,buffer_grow,4);i=0.0;lj=0.5;};
{nnn=nnnnnnnnnnnnn(00000,nnnnnnnnnnn,0);n=000;Ln=000;};
                                                     ^

After erasing the initializer of the variable i, the pos is set at the first l of local instead of the semicolon, because of which it skips to the o of local when it starts parsing j because of the pos++ at the end of the loop. Therefore, by setting pos to be one character behind, it leads to the following state:

FOUND LOCAL/GLOBAL KEYWORD:
{buf=buffer_create(32000,buffer_grow,4);localdoublei=0.0;localdoublej=0.5;};
{nnn=nnnnnnnnnnnnn(00000,nnnnnnnnnnn,0);LLLLLttttttn=000;LLLLLttttttn=000;};
                                        ^
Declared double i as local
WHILE DECLARING:
{buf=buffer_create(32000,buffer_grow,4);i=0.0;localdoublej=0.5;};
{nnn=nnnnnnnnnnnnn(00000,nnnnnnnnnnn,0);n=000;LLLLLttttttn=000;};
                                             ^
ERASE FROM CODE: i
dec_name: i
AFTER ERASING INIT:
{buf=buffer_create(32000,buffer_grow,4);i=0.0;localdoublej=0.5;};
{nnn=nnnnnnnnnnnnn(00000,nnnnnnnnnnn,0);n=000;LLLLLttttttn=000;};
                                             ^
FOUND LOCAL/GLOBAL KEYWORD:
{buf=buffer_create(32000,buffer_grow,4);i=0.0;localdoublej=0.5;};
{nnn=nnnnnnnnnnnnn(00000,nnnnnnnnnnn,0);n=000;LLLLLttttttn=000;};
                                              ^
Declared double j as local
WHILE DECLARING:
{buf=buffer_create(32000,buffer_grow,4);i=0.0;j=0.5;};
{nnn=nnnnnnnnnnnnn(00000,nnnnnnnnnnn,0);n=000;n=000;};
                                                   ^
ERASE FROM CODE: j
dec_name: j
AFTER ERASING INIT:
{buf=buffer_create(32000,buffer_grow,4);i=0.0;j=0.5;};
{nnn=nnnnnnnnnnnnn(00000,nnnnnnnnnnn,0);n=000;n=000;};
                                                   ^

Thus pos points to the right character at the end of parsing the initializer and the bug is fixed.