runtime: remove redudant tryWakeP component

Here tryWakeP can't already be true, so there is no need to combine the
values.

This CL should have no functional changes.

For #43997.
For #44313.

Change-Id: I640c7bb88a5f70c8d22f89f0b5b146b3f60c0136
Reviewed-on: https://go-review.googlesource.com/c/go/+/307911
Trust: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>

src/runtime/proc.go

@@ -3136,7 +3136,9 @@ top:
 	}
 	if gp == nil && gcBlackenEnabled != 0 {
 		gp = gcController.findRunnableGCWorker(_g_.m.p.ptr())
-		tryWakeP = tryWakeP || gp != nil
+		if gp != nil {
+			tryWakeP = true
+		}
 	}
 	if gp == nil {
 		// Check the global runnable queue once in a while to ensure fairness.