word_stem() decapitalizes words in Velox, but Java preserves capitalization.

[amitkdutta]

Bug description

@spershin found that word_stem library does not preserve the capitalization of words like Presto Java

In Presto Java:

SELECT word_stem(c0) from (values ('Reston'), ('Earnings'), ('Q2'), ('PID'), ('RuntimeError'), ('PRIZE')) t(c0);
    _col0             
--------------
 Reston       
 Earn         
 Q2           
 PID          
 RuntimeError 
 PRIZE        
(6 rows)

In Velox/Presto C++, same query returns

SELECT word_stem(c0) from (values ('Reston'), ('Earnings'), ('Q2'), ('PID'), ('RuntimeError'), ('PRIZE')) t(c0);
    _col0             
--------------
 reston       
 earn         
 q2           
 pid          
 runtimeerror 
 prize        
(6 rows)

System information

Any platform

Relevant logs

No specific logs

[amitkdutta]

CC: @yhwang @kgpai @kagamiori