symbol.replace patch:

Richards: ~586
DeltaBlue: ~558
Crypto:  ~1464
RayTrace: ~1071
EarleyBoyer: ~1762
RegExp: ~275
Splay: ~559
SplayLatency:  ~1778
NavierStokes: ~1451
PdfJS: ~ 3721
Mandreel: ~808
MandreelLatency: ~4736
Gameboy: ~5988
CodeLoad: ~8094
Box2D: ~2292
zlib: ~1785
Typescript: ~2781
----
Score (version 9): ~1623

Octane maximum resident set size: ~238932KB

master:

Richards: ~563
DeltaBlue: ~561
Crypto: ~1558
RayTrace: ~1078
EarleyBoyer: ~1650
RegExp: ~412
Splay: ~562
SplayLatency: ~1780
NavierStokes: ~1433
PdfJS: ~3610
Mandreel: ~770
MandreelLatency: ~4605
Gameboy: ~5807
CodeLoad: ~10551
Box2D: ~2242
zlib: ~1791
Typescript: ~2842
----
Score (version 9): ~1651

Octane maximum resident set size: ~235490KB