[gdb/testsuite] Fix test names in gdb.base/longjmp.exp

When running test-case gdb.base/longjmp.exp, we have:
...
PASS: gdb.base/longjmp.exp: next over setjmp (1)
  ...
PASS: gdb.base/longjmp.exp: next over setjmp (2)
...

The trailing " (1)" and " (2)" are interpreted as comments rather than parts
of the test name, and therefore this is a duplicate, which is currently not
detected by our duplicate detection mechanism (PR testsuite/29772).

Fix the duplicate by using with_test_prefix.

Tested on x86_64-linux.

gdb/testsuite/gdb.base/longjmp.exp

@@ -42,73 +42,88 @@ set bp_start_test_3 [gdb_get_line_number "patt3"]
 # Pattern 1 - simple longjmp.
 #
 
+with_test_prefix "pattern 1" {
+
+    with_test_prefix setup {
 	delete_breakpoints
 
 	gdb_test "break $bp_start_test_1" \
 	    "Breakpoint.*at.* file .*$srcfile, line.*$bp_start_test_1.*" \
-    "breakpoint at pattern 1 start"
+	    "breakpoint at pattern start"
-gdb_test "continue" "patt1.*" "continue to breakpoint at pattern 1 start"
+	gdb_test "continue" "patt1.*" "continue to breakpoint at pattern start"
 
 	# set safe-net break
 	gdb_test "break $bp_miss_step_1" \
 	    "Breakpoint.*at.* file .*$srcfile, line.*$bp_miss_step_1.*" \
-    "breakpoint at miss_step_1"
+	    "breakpoint at safety net"
+    }
 
-gdb_test "next" "longjmps\\+\\+;.*" "next over setjmp (1)"
+    gdb_test "next" "longjmps\\+\\+;.*" "next over setjmp"
-gdb_test "next" "longjmp \\(env, 1\\);.*" "next to longjmp (1)"
+    gdb_test "next" "longjmp \\(env, 1\\);.*" "next to longjmp"
 
-set msg "next over longjmp(1)"
+    set msg "next over longjmp"
     gdb_test_multiple "next" $msg {
 	-re ".*patt1.*$gdb_prompt $" {
 	    pass $msg
-	gdb_test "next" "resumes\\+\\+.*" "next into else block (1)"
+	    gdb_test "next" "resumes\\+\\+.*" "next into else block"
-	gdb_test "next" "miss_step_1.*" "next into safety net (1)"
+	    gdb_test "next" "miss_step_1.*" "next into safety net"
 	}
 	-re "miss_step_1.*$gdb_prompt $" {
 	    fail $msg
 	}
     }
+}
 
 #
 # Pattern 2 - longjmp from an inner function.
 #
 
+with_test_prefix "pattern 2" {
+
+    with_test_prefix setup {
 	delete_breakpoints
 
 	gdb_test "break $bp_start_test_2" \
 	    "Breakpoint.*at.* file .*$srcfile, line.*$bp_start_test_2.*" \
-    "breakpoint at pattern 2 start"
+	    "breakpoint at pattern start"
-gdb_test "continue" "patt2.*" "continue to breakpoint at pattern 2 start"
+	gdb_test "continue" "patt2.*" "continue to breakpoint at pattern start"
 
 	# set safe-net break
 	gdb_test "break $bp_miss_step_2" \
 	    "Breakpoint.*at.* file .*$srcfile, line.*$bp_miss_step_2.*" \
-    "breakpoint at miss_step_2"
+	    "breakpoint at safety net"
+    }
 
-gdb_test "next" "call_longjmp.*" "next over setjmp (2)"
+    gdb_test "next" "call_longjmp.*" "next over setjmp"
 
-set msg "next over call_longjmp (2)"
+    set msg "next over call_longjmp"
     gdb_test_multiple "next" $msg {
 	-re ".*patt2.*$gdb_prompt $" {
 	    pass $msg
 
-	gdb_test "next" "resumes\\+\\+.*" "next into else block (2)"
+	    gdb_test "next" "resumes\\+\\+.*" "next into else block"
-	gdb_test "next" "miss_step_2.*" "next into safety net (2)"
+	    gdb_test "next" "miss_step_2.*" "next into safety net"
 	}
 	-re "miss_step_2.*$gdb_prompt $" {
 	    fail $msg
 	}
     }
+}
 
 #
 # Pattern 3 - setjmp/longjmp inside stepped-over function.
 #
 
+with_test_prefix "pattern 3" {
+
+    with_test_prefix setup {
 	delete_breakpoints
 
 	gdb_test "break $bp_start_test_3" \
 	    "Breakpoint.*at.* file .*$srcfile, line.*$bp_start_test_3.*" \
-    "breakpoint at pattern 3 start"
+	    "breakpoint at pattern start"
-gdb_test "continue" "patt3.*" "continue to breakpoint at pattern 3 start"
+	gdb_test "continue" "patt3.*" "continue to breakpoint at pattern start"
+    }
 
-gdb_test "next" "longjmp caught.*" "next over patt3"
+    gdb_test "next" "longjmp caught.*" "next over pattern"
+}