nullptr deref in ConstantFoldNode with malformed input

[niv]

Ran on minmised nwscript.nss with all optimisations enabled.

Stacks vary between crashes, all end up at the same frame though.

==57507==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000008 (pc 0x000104a712bc bp 0x00016b3b4fe0 sp 0x00016b3b4780 T0)
==57507==The signal is caused by a READ memory access.
==57507==Hint: address points to the zero page.
    #0 0x104a712bc in CScriptCompiler::ConstantFoldNode(CScriptParseTreeNode*, int)+0x2110 (afl-diag:arm64+0x1000312bc)
    #1 0x104a90508 in CScriptCompiler::GenerateIdentifiersFromConstantVariables(CScriptParseTreeNode*)+0x1498 (afl-diag:arm64+0x100050508)
    #2 0x104b4fc64 in CScriptCompiler::GenerateParseTree()+0x31000 (afl-diag:arm64+0x10010fc64)
    #3 0x104b12758 in CScriptCompiler::HandleToken()+0xb8 (afl-diag:arm64+0x1000d2758)
    #4 0x104b180e8 in CScriptCompiler::ParseCharacterSemicolon()+0x108 (afl-diag:arm64+0x1000d80e8)
    #5 0x104b1aa2c in CScriptCompiler::ParseNextCharacter(int, int, char const*, int)+0xf30 (afl-diag:arm64+0x1000daa2c)
    #6 0x104b5ab08 in CScriptCompiler::ParseSource(char const*, int)+0x258 (afl-diag:arm64+0x10011ab08)
    #7 0x104a6d52c in CScriptCompiler::CompileScriptChunk(CExoString const&, int)+0x400 (afl-diag:arm64+0x10002d52c)
    #8 0x104b5b88c in main+0x720 (afl-diag:arm64+0x10011b88c)
    #9 0x18c6c4270  (<unknown module>)

Above stack generated with asan enabled when attempting to compile

id:000099,sig:11,src:001437+001621,time:2661673,execs:46244036,op:splice,rep:10.txt