debug/gosym: remove need for gotest to run preparatory commands.

Put them into the Makefile instead. One dependency mechanism is enough.

R=rsc
CC=golang-dev
https://golang.org/cl/4331043

src/pkg/debug/gosym/Makefile

@@ -11,3 +11,9 @@ GOFILES=\
 
 include ../../../Make.pkg
 
+test: make-pclinetest
+
+testshort: make-pclinetest
+
+make-pclinetest:
+	@if [ "`uname`-`uname -m`" = Linux-x86_64 -a $(GOARCH) = amd64 ]; then mkdir -p _test && $(AS) pclinetest.s && $(LD) -E main -o _test/pclinetest pclinetest.$O; fi

src/pkg/debug/gosym/pclntab_test.go

@@ -143,9 +143,6 @@ func TestLineAline(t *testing.T) {
 	}
 }
 
-// gotest: if [ "$(uname)-$(uname -m)" = Linux-x86_64 -a "$GOARCH" = amd64 ]; then
-// gotest:    mkdir -p _test && $AS pclinetest.s && $LD -E main -o _test/pclinetest pclinetest.$O
-// gotest: fi
 func TestPCLine(t *testing.T) {
 	if !dotest() {
 		return