[compiler] Implement compileStringLiteral()

[hihiboss]

Subject
compiler

Detail
Implement compileStringLiteral() with the heap.

It should be implemented after defining the heap tracer.

Reference
#361
#362

[zeroFruit]

Assign it to me! I will review heap pr tomorrow

[hihiboss]

@zeroFruit
ok! I'll assign it to you!