[gdb/testsuite] Bail out after 1 timeout in test_complete_prefix_range_re

In test_complete_prefix_range_re we stop testing the range after 3 consecutive
timeouts.

Handle timeouts more rigorously by stopping testing after the first timeout.

Tested on x86_64-linux.

gdb/testsuite/ChangeLog:

2020-03-19  Tom de Vries  <tdevries@suse.de>

	* lib/completion-support.exp (test_complete_prefix_range_re): Stop
	testing after the first timeout.

---
 gdb/testsuite/lib/completion-support.exp | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/gdb/testsuite/lib/completion-support.exp b/gdb/testsuite/lib/completion-support.exp
index 18eac827f5..2bf3acd1f4 100644
--- a/gdb/testsuite/lib/completion-support.exp
+++ b/gdb/testsuite/lib/completion-support.exp
@@ -311,20 +311,11 @@ proc test_complete_prefix_range_re {input completion_re start {end -1}} {
 	set end [string length $input]
     }
 
-    set timeouts 0
-    set max_timeouts 3
     for {set i $start} {$i < $end} {incr i} {
 	set line [string range $input 0 $i]
 	set res [test_gdb_complete_unique_re "$line" $completion_re]
 	if { $res == -1 } {
-	    incr timeouts
-	} else {
-	    if { $timeouts > 0 } {
-		set timeouts 0
-	    }
-	}
-	if { $timeouts == $max_timeouts } {
-	    verbose -log "Consecutive timeouts in test_complete_prefix_range_re, giving up"
+	    verbose -log "Timeout in test_complete_prefix_range_re, giving up"
 	    break
 	}
     }