assert(VM_Version::supports_sse2()) failed: must support

Regression after my fix for 7079329: Adjust allocation prefetching for T4. The failure happened when VM runs on old Pentium III which does not have SSE2:

CPU:total 2 (1 cores per cpu, 1 threads per core) family 6 model 11 stepping 1, cmov, cx8, fxsr, mmx, sse

V [libjvm.so+0xb1528e] void report_vm_error(const char*,int,const char*,const char*)+0x53a;; void report_vm_error(const char*,int,const char*,const char*)+0x53a
V [libjvm.so+0x4bc98d] void Assembler::prefetchnta(Address)+0x179;; void Assembler::prefetchnta(Address)+0x179
V [libjvm.so+0x27ca91] void prefetchAllocNTANode::emit(CodeBuffer&,PhaseRegAlloc*)const+0x159;; void prefetchAllocNTANode::emit(CodeBuffer&,PhaseRegAlloc*)const+0x159
V [libjvm.so+0x9cb287] unsigned Compile::scratch_emit_size(const Node*)+0x42b;; unsigned Compile::scratch_emit_size(const Node*)+0x42b
V [libjvm.so+0x164a58a] unsigned MachNode::size(PhaseRegAlloc*)const+0x2e;; unsigned MachNode::size(PhaseRegAlloc*)const+0x2e
V [libjvm.so+0x18ff7b9] void Compile::shorten_branches(unsigned*,int&,int&,int&)+0x491;; void Compile::shorten_branches(unsigned*,int&,int&,int&)+0x491
V [libjvm.so+0x1903673] CodeBuffer*Compile::init_buffer(unsigned*)+0x333;; CodeBuffer*Compile::init_buffer(unsigned*)+0x333
V [libjvm.so+0x18fe509] void Compile::Output()+0x925;; void Compile::Output()+0x925
V [libjvm.so+0x9d6753] void Compile::Code_Gen()+0x753;; void Compile::Code_Gen()+0x753