tools: update V8 gypfiles for RISC-V
With the inclusion of the RISC-V 32-bit support in V8 the directory src/heap/base/asm/riscv64 has been renamed to riscv.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
With the inclusion of the RISC-V 32-bit support in V8 the directory src/heap/base/asm/riscv64 has been renamed to riscv.