runtime: rename gothrow to throw

Rename "gothrow" to "throw" now that the C version of "throw"
is no longer needed.

This change is purely mechanical except in panic.go where the
old version of "throw" has been deleted.

sed -i "" 's/[[:<:]]gothrow[[:>:]]/throw/g' runtime/*.go

Change-Id: Icf0752299c35958b92870a97111c67bcd9159dc3
Reviewed-on: https://go-review.googlesource.com/2150
Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
diff --git a/src/runtime/sys_ppc64x.go b/src/runtime/sys_ppc64x.go
index b0c0331..bd182e3 100644
--- a/src/runtime/sys_ppc64x.go
+++ b/src/runtime/sys_ppc64x.go
@@ -12,7 +12,7 @@
 // and then did an immediate Gosave.
 func gostartcall(buf *gobuf, fn, ctxt unsafe.Pointer) {
 	if buf.lr != 0 {
-		gothrow("invalid use of gostartcall")
+		throw("invalid use of gostartcall")
 	}
 	buf.lr = buf.pc
 	buf.pc = uintptr(fn)
@@ -33,5 +33,5 @@
 		}
 	}
 	print("runtime: pc=", hex(buf.pc), " ", hex(inst), "\n")
-	gothrow("runtime: misuse of rewindmorestack")
+	throw("runtime: misuse of rewindmorestack")
 }