Fix the syntax of allocating new array in ICU_getScript

`new char(value)` allocates a single char instead of a char array,
and it's incorrect.

Bug: 185151367
Test: atest CtsLibcoreTestCases:libcore.libcore.icu.ICUTest
Change-Id: I01a1e7438795b7122005f534bb83d10c2321752b
1 file changed