[gdb/testsuite] Fix duplicate test name in gdb.mi/mi-sym-info.exp

Since commit 2d61316c32a "[gdb/testsuite] Fix buffer full errors in
gdb.mi/mi-sym-info.exp", we have a duplicate test name:
...
Running src/gdb/testsuite/gdb.mi/mi-sym-info.exp ...
DUPLICATE: gdb.mi/mi-sym-info.exp: List all variables
...

This is caused by a copy-paste accident: the idea was to copy the test, edit
it, and then remove the old test, but I forgot to remove the old one.
Remove it now.

Tested on x86_64-linux.

gdb/testsuite/ChangeLog:

2021-04-30  Tom de Vries  <tdevries@suse.de>

	* gdb.mi/mi-sym-info.exp: Remove duplicate test.

gdb/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2021-04-30  Tom de Vries  <tdevries@suse.de>
+
+	* gdb.mi/mi-sym-info.exp: Remove duplicate test.
+
 2021-04-29  Tom de Vries  <tdevries@suse.de>
 
 	PR testsuite/27786

gdb/testsuite/gdb.mi/mi-sym-info.exp

@@ -150,39 +150,6 @@ gdb_test_multiple $cmd ${testname} -prompt "${mi_gdb_prompt}$" {
     }
 }
 
-with_timeout_factor 2 {
-    set testname "List all variables"
-    set cmd "115-symbol-info-variables --include-nondebug"
-    set state 0
-    gdb_test_multiple $cmd ${testname} -prompt "${mi_gdb_prompt}$" {
-	-re "115\\^done,symbols=\{" {
-	    if { $state == 0 } { set state 1 }
-	    exp_continue
-	}
-	-re "debug=\\\[${symtab_re}" {
-	    if { $state == 1 } { set state 2 }
-	    exp_continue
-	}
-	-re ",${symtab_re}" {
-	    exp_continue
-	}
-	-re "\\\],nondebug=\\\[" {
-	    if { $state == 2 } { set state 3 }
-	    exp_continue
-	}
-	-re "\{address=${qstr},name=${qstr}\}," {
-	    exp_continue
-	}
-	-re "\{address=${qstr},name=${qstr}\}\\\]\}\r\n${mi_gdb_prompt}$" {
-	    if { $state == 3 } {
-		pass $gdb_test_name
-	    } else {
-		fail $gdb_test_name
-	    }
-	}
-    }
-}
-
 with_timeout_factor 2 {
     set testname "List all variables"
     set cmd "115-symbol-info-variables --include-nondebug"