cl: switch debug symbols with LLGO_DEBUG

cl/cltest/cltest.go

@@ -130,10 +130,10 @@ func testFrom(t *testing.T, pkgDir, sel string, byLLGen bool) {
 	out := pkgDir + "/out.ll"
 	dbg := isDbgSymEnabled(pkgDir + "/flags.txt")
 	if dbg {
-		cl.EnableDebugSymbols()
+		cl.EnableDebugSymbols(true)
+		defer cl.EnableDebugSymbols(false)
 		cl.DebugSymbols() // just for coverage
 	}
-	defer cl.DisableDebugSymbols()
 	b, err := os.ReadFile(out)
 	if err != nil {
 		t.Fatal("ReadFile failed:", err)

cl/compile.go

@@ -58,12 +58,8 @@ func SetDebug(dbgFlags dbgFlags) {
 }
 
 // EnableDebugSymbols enables debug symbols.
-func EnableDebugSymbols() {
-	debugSymbols = true
-}
-
-func DisableDebugSymbols() {
-	debugSymbols = false
+func EnableDebugSymbols(b bool) {
+	debugSymbols = b
 }
 
 func DebugSymbols() bool {