internal/reflectlite: remove unused mapType

Change-Id: I715186c053bc9911b912e69904735c9498bf9c13
Reviewed-on: https://go-review.googlesource.com/c/go/+/580376
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>

src/internal/reflectlite/reflect_mirror_test.go

@@ -24,7 +24,6 @@ var typeNames = []string{
 	"chanType",
 	"funcType",
 	"interfaceType",
-	"mapType",
 	"ptrType",
 	"sliceType",
 	"structType",

src/internal/reflectlite/type.go

@@ -111,20 +111,6 @@ type funcType = abi.FuncType
 
 type interfaceType = abi.InterfaceType
 
-// mapType represents a map type.
-type mapType struct {
-	rtype
-	Key    *abi.Type // map key type
-	Elem   *abi.Type // map element (value) type
-	Bucket *abi.Type // internal bucket structure
-	// function for hashing keys (ptr to key, seed) -> hash
-	Hasher     func(unsafe.Pointer, uintptr) uintptr
-	KeySize    uint8  // size of key slot
-	ValueSize  uint8  // size of value slot
-	BucketSize uint16 // size of bucket
-	Flags      uint32
-}
-
 // ptrType represents a pointer type.
 type ptrType = abi.PtrType