Remove obsolete check from skip_compile_feature_tests

skip_compile_feature_tests checks for "Command not supported on this
host", but this error was removed by commit e8d8cce6 ("Import mkdtemp
gnulib module, fix mingw build").  This patch removes the obsolete
test.

gdb/testsuite/lib/compile-support.exp

@@ -26,9 +26,6 @@ proc skip_compile_feature_tests {} {
 	"Could not load libcc1.*\r\n$gdb_prompt $" {
 	    set result 1
 	}
-	-re "Command not supported on this host\\..*\r\n$gdb_prompt $" {
-	    set result 1
-	}
 	-re "\r\n$gdb_prompt $" {
 	}
     }