PPC/s390: [wasm-simd] Implement load extend with 4 and 8 lanes on IA32

Port 4648b83c

Original Commit Message:

    This CL implements 4 of the 6 load extend operations. The added
    opcodes include: I16x8Load8x8S, I16x8Load8x8U, I32x4Load16x4S,
    I32x4Load16x4U.

R=zhiguo.zhou@intel.com, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Change-Id: I3a3308522a69dba78c7a8d6b3ff4b25d25f2e569
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1999492Reviewed-by: Junliang Yan <jyan@ca.ibm.com>
Commit-Queue: Milad Farazmand <miladfar@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#65758}

src/compiler/backend/ppc/instruction-selector-ppc.cc

@@ -2450,6 +2450,9 @@ void InstructionSelector::VisitI64x2ShrU(Node* node) { UNIMPLEMENTED(); }
 void InstructionSelector::VisitF64x2Min(Node* node) { UNIMPLEMENTED(); }
 
 void InstructionSelector::VisitF64x2Max(Node* node) { UNIMPLEMENTED(); }
+
+void InstructionSelector::VisitLoadTransform(Node* node) { UNIMPLEMENTED(); }
+
 // static
 MachineOperatorBuilder::Flags
 InstructionSelector::SupportedMachineOperatorFlags() {

src/compiler/backend/s390/instruction-selector-s390.cc

@@ -2857,6 +2857,8 @@ void InstructionSelector::VisitF64x2Max(Node* node) { UNIMPLEMENTED(); }
 
 void InstructionSelector::VisitF64x2ExtractLane(Node* node) { UNIMPLEMENTED(); }
 
+void InstructionSelector::VisitLoadTransform(Node* node) { UNIMPLEMENTED(); }
+
 // static
 MachineOperatorBuilder::Flags
 InstructionSelector::SupportedMachineOperatorFlags() {