Tighten the growth/fragmentation regexp to only allow an optional z.

profile/legacy_profile.go

 
 	hexNumberRE = regexp.MustCompile(`0x[0-9a-f]+`)
 
-	growthHeaderRE = regexp.MustCompile(`heap profile: *(\d+): *(\d+) *\[ *(\d+): *(\d+) *\] @ growth.?`)
+	growthHeaderRE = regexp.MustCompile(`heap profile: *(\d+): *(\d+) *\[ *(\d+): *(\d+) *\] @ growthz?`)
 
-	fragmentationHeaderRE = regexp.MustCompile(`heap profile: *(\d+): *(\d+) *\[ *(\d+): *(\d+) *\] @ fragmentation.?`)
+	fragmentationHeaderRE = regexp.MustCompile(`heap profile: *(\d+): *(\d+) *\[ *(\d+): *(\d+) *\] @ fragmentationz?`)
 
 	threadzStartRE = regexp.MustCompile(`--- threadz \d+ ---`)
 	threadStartRE  = regexp.MustCompile(`--- Thread ([[:xdigit:]]+) \(name: (.*)/(\d+)\) stack: ---`)