cmd/compile: rename instType -> instanceType

This is to keep in alignment with the naming in go/types.

Change-Id: I19ded29b39665d7b892fdbc8e92c7f15caf7ab66
Reviewed-on: https://go-review.googlesource.com/c/go/+/350950
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Trust: Dan Scales <danscales@google.com>

src/cmd/compile/internal/typecheck/iexport.go

@@ -255,7 +255,7 @@ const (
 	structType
 	interfaceType
 	typeParamType
-	instType
+	instanceType // Instantiation of a generic type
 	unionType
 )
 
@@ -893,7 +893,7 @@ func (w *exportWriter) doTyp(t *types.Type) {
 		if strings.Index(s.Name, "[") < 0 {
 			base.Fatalf("incorrect name for instantiated type")
 		}
-		w.startType(instType)
+		w.startType(instanceType)
 		w.pos(t.Pos())
 		// Export the type arguments for the instantiated type. The
 		// instantiated type could be in a method header (e.g. "func (v

src/cmd/compile/internal/typecheck/iimport.go

@@ -821,7 +821,7 @@ func (r *importReader) typ1() *types.Type {
 		}
 		return n.Type()
 
-	case instType:
+	case instanceType:
 		if r.p.exportVersion < iexportVersionGenerics {
 			base.Fatalf("unexpected instantiation type")
 		}