Fix Windows-target testing in mi_gdb_file_cmd

[Joseph Myers]

Similar to my recent fix for gdb_file_cmd, mi_gdb_file_cmd also runs
into problems when GCC has created foo.exe given "-o foo".

Apply exactly the same fix there as in gdb_file_cmd.  This allows many
more tests to succeed for Windows target that previously fell over.

2020-11-13  Joseph Myers  <joseph@codesourcery.com>

	* lib/mi-support.exp (mi_gdb_file_cmd): Check for case where
	$arg.exe exists but $arg does not.

diff --git a/gdb/testsuite/lib/mi-support.exp b/gdb/testsuite/lib/mi-support.exp
index 8e7b0ab79e..bfc8edcd8d 100644
--- a/gdb/testsuite/lib/mi-support.exp
+++ b/gdb/testsuite/lib/mi-support.exp
@@ -505,6 +505,11 @@ proc mi_gdb_file_cmd { arg } {
     global last_loaded_file
     upvar timeout timeout
 
+    # GCC for Windows target may create foo.exe given "-o foo".
+    if { ![file exists $arg] && [file exists "$arg.exe"] } {
+	set arg "$arg.exe"
+    }
+
     set last_loaded_file $arg
 
     if [is_remote host] {

-- 
Joseph S. Myers
joseph@codesourcery.com