I am crashing the program when using redundant paranthesis to create arrays
```
y ← 1 ((2))
==============================================================================
Assertion failed: !sub_val->is_simple_scalar()
in Function: PointerCell
in file: PointerCell.cc:30
Call stack:
----------------------------------------
-- Stack trace at PointerCell.cc:30
----------------------------------------
0x7F7F24566B25 __libc_start_main
0x556355C13C16 main
0x556355D6C816 Workspace::immediate_execution(bool)
0x556355C667B7 Command::process_line()
0x556355C67275 Command::do_APL_expression(UCS_string&)
0x556355C73728 StatementList::fix(UCS_string const&, char const*)
0x556355C7316C Executable::parse_body_line(Function_Line, UCS_string const&, bool, bool, char const*, bool)
0x556355C9D74A Parser::parse(UCS_string const&, Token_string&) const
0x556355C9D3CB Parser::parse(Token_string const&, Token_string&) const
0x556355C9D14C Parser::parse_statement(Token_string&)
0x556355C9C941 Parser::collect_constants(Token_string&)
0x556355C9C64E Parser::create_vector_value(Token_string&, int, int)
0x556355CA779E PointerCell::PointerCell(Value*, Value&)
0x556355C2A878 do_Assert(char const*, char const*, char const*, int)
========================================
SI stack:
==============================================================================
*** Command::process_line() caught other exception ***
Goodbye.
Session duration: 39.844 seconds
Process apl finished
```
This is not happenning for a single pair y ← 1 (2)