all: fix misspellings in comments

Change-Id: I121847e7f68c602dd8e9ecddfc41b547f8a86f10
Reviewed-on: https://go-review.googlesource.com/c/go/+/734361
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Robert Griesemer <gri@google.com>
Reviewed-by: Junyang Shao <shaojunyang@google.com>

src/cmd/compile/internal/ssagen/ssa.go

@@ -7795,7 +7795,7 @@ func AddrAuto(a *obj.Addr, v *ssa.Value) {
 // Call returns a new CALL instruction for the SSA value v.
 // It uses PrepareCall to prepare the call.
 func (s *State) Call(v *ssa.Value) *obj.Prog {
-	pPosIsStmt := s.pp.Pos.IsStmt() // The statement-ness fo the call comes from ssaGenState
+	pPosIsStmt := s.pp.Pos.IsStmt() // The statement-ness of the call comes from ssaGenState
 	s.PrepareCall(v)
 
 	p := s.Prog(obj.ACALL)

src/simd/archsimd/_gen/simdgen/gen_simdMachineOps.go

@@ -181,7 +181,7 @@ func writeSIMDMachineOps(ops []Operation) *bytes.Buffer {
 		}
 		hasMerging = gOp.hasMaskedMerging(maskType, shapeOut)
 		if hasMerging && !resultInArg0 {
-			// We have to copy the slice here becasue the sort will be visible from other
+			// We have to copy the slice here because the sort will be visible from other
 			// aliases when no reslicing is happening.
 			newIn := make([]Operand, len(op.In), len(op.In)+1)
 			copy(newIn, op.In)

src/simd/archsimd/_gen/simdgen/gen_simdssa.go

@@ -133,7 +133,7 @@ func writeSIMDSSA(ops []Operation) *bytes.Buffer {
 		if mem == NoMem && op.hasMaskedMerging(maskType, shapeOut) {
 			regShapeMerging := regShape
 			if shapeOut != OneVregOutAtIn {
-				// We have to copy the slice here becasue the sort will be visible from other
+				// We have to copy the slice here because the sort will be visible from other
 				// aliases when no reslicing is happening.
 				newIn := make([]Operand, len(op.In), len(op.In)+1)
 				copy(newIn, op.In)