Adjust conditional for broken legacy case

DejaGnu has always required testsuites to be rooted in a directory
named exactly "testsuite" but older versions happened to work even
if this requirement was violated.  Special handling for this broken
case was included, but the conditional to invoke this handling was
too narrow and missed several cases in the GNU Automake testsuite.

ChangeLog

@@ -1,3 +1,12 @@
+2021-06-29  Jacob Bachmeyer  <[email protected]>
+
+	PR49250
+
+	* runtest.exp: Adjust detection logic for deprecated broken legacy
+	case of a testsuite not actually in a testsuite/ directory.
+
+	This was never supported but happened to work in older versions.
+
 2021-05-22  Jacob Bachmeyer  <[email protected]>
 
 	* Makefile.am (TESTSUITE_FILES): Correct oversight.

runtest.exp

@@ -741,7 +741,7 @@ if { [file tail $srcdir] eq "testsuite" } {
     set testsuitedir $base_dir
     set testbuilddir $base_dir
 } else {
-    if { $testsuitedir eq "testsuite" && $srcdir eq "." && $objdir eq "." } {
+    if { $testsuitedir eq "testsuite" && $testbuilddir eq "testsuite" } {
 	# Broken legacy case -- testsuite not actually in testsuite/
 	# Produce a warning, but continue.
 	send_error "WARNING: testsuite is not in a testsuite/ directory.\n"