Revert^4 "Implement Dot Product Vectorization for x86"

This reverts commit 8e895008a3e2f2813bb46cb0c6bc76884e46e9ac.

Reason for revert: The test failure seems unrelated.
Bug: 144947842

Change-Id: I7b437f0443d71a5c762e1a8372564ed989971cc9
diff --git a/compiler/utils/x86/assembler_x86.cc b/compiler/utils/x86/assembler_x86.cc
index 166aec8..55f7691 100644
--- a/compiler/utils/x86/assembler_x86.cc
+++ b/compiler/utils/x86/assembler_x86.cc
@@ -2268,6 +2268,20 @@
 }
 
 
+void X86Assembler::vpmaddwd(XmmRegister dst, XmmRegister src1, XmmRegister src2) {
+  DCHECK(CpuHasAVXorAVX2FeatureFlag());
+  AssemblerBuffer::EnsureCapacity ensured(&buffer_);
+  uint8_t ByteZero = 0x00, ByteOne = 0x00;
+  ByteZero = EmitVexPrefixByteZero(/* is_twobyte_form=*/ true);
+  X86ManagedRegister vvvv_reg = X86ManagedRegister::FromXmmRegister(src1);
+  ByteOne = EmitVexPrefixByteOne(/*R=*/ false, vvvv_reg, SET_VEX_L_128, SET_VEX_PP_66);
+  EmitUint8(ByteZero);
+  EmitUint8(ByteOne);
+  EmitUint8(0xF5);
+  EmitXmmRegisterOperand(dst, src2);
+}
+
+
 void X86Assembler::phaddw(XmmRegister dst, XmmRegister src) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitUint8(0x66);