use readelf in a way that it prints less output

testdata/scripts/basic.txt

@@ -18,9 +18,9 @@ cmp stderr main.stderr
 grep $WORK main
 
 # The default build includes DWARF and the symbol table.
-exec readelf --section-details --symbols main
+exec readelf --section-headers main
-stdout 'debug_info$'
+stdout 'debug_info'
-stdout 'globalVar'
+stdout '\.symtab'
 
 # The default build includes full non-trimmed paths.
 grep $WORK main
@@ -34,9 +34,9 @@ exec go build -a -trimpath -toolexec=garble main.go
 exec ./main
 cmp stderr main.stderr
 
-exec readelf --section-details --symbols main
+exec readelf --section-headers main
-! stdout 'debug_info$'
+! stdout 'debug_info'
-! stdout 'globalVar'
+! stdout '\.symtab'
 
 ! grep $WORK main