re PR go/83794 (misc/cgo/test uses gigabytes of memory)

PR go/83794
    misc/cgo/test: avoid endless loop when we can't parse notes
    
    Reviewed-on: https://go-review.googlesource.com/87416

From-SVN: r256553

gcc/go/gofrontend/MERGE

@@ -1,4 +1,4 @@
-1176dd2b53f2d2b826b599a126f3f9828283cec3
+fe8481db9f5b37eb9a0c329673789eaaf1335598
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

libgo/misc/cgo/test/buildid_linux.go

@@ -27,6 +27,7 @@ func testBuildID(t *testing.T) {
 	defer f.Close()
 
 	c := 0
+sections:
 	for i, s := range f.Sections {
 		if s.Type != elf.SHT_NOTE {
 			continue
@@ -47,7 +48,7 @@ func testBuildID(t *testing.T) {
 
 			if len(d) < 12 {
 				t.Logf("note section %d too short (%d < 12)", i, len(d))
-				continue
+				continue sections
 			}
 
 			namesz := f.ByteOrder.Uint32(d)
@@ -59,7 +60,7 @@ func testBuildID(t *testing.T) {
 
 			if int(12+an+ad) > len(d) {
 				t.Logf("note section %d too short for header (%d < 12 + align(%d,4) + align(%d,4))", i, len(d), namesz, descsz)
-				continue
+				continue sections
 			}
 
 			// 3 == NT_GNU_BUILD_ID