tracing/runtime: Regenerate (refresh support for Go1.14 and Go1.15)

Go1.14.10 and Go1.15.3 changed internal structure of g:

https://github.com/golang/go/commit/878da0bf881b (go1.14)
https://github.com/golang/go/commit/bf79f91d3dc4 (go1.15)

tracing/internal/xruntime/zruntime_g_go1.14.go

@@ -50,6 +50,10 @@ type g struct {
 	// copying needs to acquire channel locks to protect these
 	// areas of the stack.
 	activeStackChans bool
+	// parkingOnChan indicates that the goroutine is about to
+	// park on a chansend or chanrecv. Used to signal an unsafe point
+	// for stack shrinking. It's a boolean value, but is updated atomically.
+	parkingOnChan uint8
 
 	raceignore     int8     // ignore race detection events
 	sysblocktraced bool     // StartTrace has emitted EvGoInSyscall about this goroutine

tracing/internal/xruntime/zruntime_g_go1.15.go

@@ -50,6 +50,10 @@ type g struct {
 	// copying needs to acquire channel locks to protect these
 	// areas of the stack.
 	activeStackChans bool
+	// parkingOnChan indicates that the goroutine is about to
+	// park on a chansend or chanrecv. Used to signal an unsafe point
+	// for stack shrinking. It's a boolean value, but is updated atomically.
+	parkingOnChan uint8
 
 	raceignore     int8     // ignore race detection events
 	sysblocktraced bool     // StartTrace has emitted EvGoInSyscall about this goroutine