src/buildall.bash: remove linux-386-387 target

Support for GO386=387 is being dropped in Go 1.16. There
is no need for the target to be available for testing on
the master branch (where Go 1.16 development is ongoing).

For #40255.

Change-Id: I4a4ee80b0c0a535b6b0b246fe991f26964eb07ca
Reviewed-on: https://go-review.googlesource.com/c/go/+/257963
Reviewed-by: Ian Lance Taylor <[email protected]>
Trust: Dmitri Shuralyov <[email protected]>

Author: dmitshur

src/buildall.bash

@@ -37,7 +37,6 @@ GOROOT="$(cd .. && pwd)"
 
 gettargets() {
 	../bin/go tool dist list | sed -e 's|/|-|'
-	echo linux-386-387
 	echo linux-arm-arm5
 }
 
@@ -64,15 +63,11 @@ do
 	echo "### Building $target"
 	export GOOS=$(echo $target | sed 's/-.*//')
 	export GOARCH=$(echo $target | sed 's/.*-//')
-	unset GO386 GOARM
+	unset GOARM
 	if [ "$GOARCH" = "arm5" ]; then
 		export GOARCH=arm
 		export GOARM=5
 	fi
-	if [ "$GOARCH" = "387" ]; then
-		export GOARCH=386
-		export GO386=387
-	fi
 
 	# Build and vet everything.
 	# cmd/go/internal/work/exec.go enables the same vet flags during go test of std cmd