remove now-redundant len shortcut in _originalNames

As Paul Scheduikat points out, the loop already does not start
if the length of name is less than minHashLength.

                       │     old     │             new              │
                       │   sec/op    │   sec/op     vs base         │
    AbiOriginalNames-8   135.6µ ± 1%   135.5µ ± 0%  ~ (p=1.000 n=7)

reflect_abi_code.go

@@ -24,10 +24,6 @@ package main
 
 //disabledgo:linkname _originalNames internal/abi._originalNames
 func _originalNames(name string) string {
-	if len(name) < minHashLength {
-		// The name is too short to be obfuscated.
-		return name
-	}
 	// We can stop once there aren't enough bytes to fit another obfuscated name.
 	for i := 0; i <= len(name)-minHashLength; {
 		switch name[i] {