Remove 0 bytes when sanitizing identifiers

Port of 95ea78048a from v3.

conn.go

@@ -78,7 +78,8 @@ type Identifier []string
 func (ident Identifier) Sanitize() string {
 	parts := make([]string, len(ident))
 	for i := range ident {
-		parts[i] = `"` + strings.Replace(ident[i], `"`, `""`, -1) + `"`
+		s := strings.Replace(ident[i], string([]byte{0}), "", -1)
+		parts[i] = `"` + strings.Replace(s, `"`, `""`, -1) + `"`
 	}
 	return strings.Join(parts, ".")
 }

conn_test.go

@@ -647,6 +647,10 @@ func TestIdentifierSanitize(t *testing.T) {
 			ident:    pgx.Identifier{`you should " not do this`, `please don't`},
 			expected: `"you should "" not do this"."please don't"`,
 		},
+		{
+			ident:    pgx.Identifier{`you should ` + string([]byte{0}) + `not do this`},
+			expected: `"you should not do this"`,
+		},
 	}
 
 	for i, tt := range tests {