CVE-2020-1912: Out-of-bounds Read and Out-of-bounds Write in Facebook Hermes

The vulnerability stems from improper handling of generator inner functions during lazy compilation. The commit adds 'isGeneratorInnerFunction' tracking through LazySource/LazyCompilationData structures. The vulnerable functions are those responsible for: 1) Generating ES5 functions (genES5Function) without properly setting the generator inner function flag, leading to incorrect scope chain resolution. 2) Lazy function restoration (doLazyFunction) that didn't account for generator context. These omissions would cause memory access miscalculations when resolving variables in nested generator functions, enabling OOB read/write through crafted JavaScript.