testsuite: Enable reduced parallel batch sizes

Various aarch64 tests attempt to reduce the batch size for parallel test
execution to a single test per batch, but it looks like the necessary
changes to gcc_parallel_test_run_p were accidentally omitted when the
aarch64-*-acle-asm.exp files were merged.  This patch corrects that
omission.

This does have a measurable performance impact when running a limited
number of tests.  For example, in aarch64-sve-acle-asm.exp the use of
torture options results in 16 compiler executions for each test; when
running two such tests I observed a total test duration of 3m39 without
this patch, and 1m55 with the patch.  A full batch of 10 tests would
have taken over 15 minutes to run on this machine.

gcc/testsuite/ChangeLog:

	* lib/gcc-defs.exp
	(gcc_runtest_parallelize_limit_minor): New global variable.
	(gcc_parallel_test_run_p): Use new variable for batch size.

Author: andrewcarlotti

gcc/testsuite/lib/gcc-defs.exp

@@ -172,6 +172,7 @@ if { [info exists env(GCC_RUNTEST_PARALLELIZE_DIR)] \
      && [info procs gcc_parallelize_saved_runtest_file_p] == [list] } then {
     global gcc_runtest_parallelize_counter
     global gcc_runtest_parallelize_counter_minor
+    global gcc_runtest_parallelize_limit_minor
     global gcc_runtest_parallelize_enable
     global gcc_runtest_parallelize_dir
     global gcc_runtest_parallelize_last
@@ -212,13 +213,15 @@ if { [info exists env(GCC_RUNTEST_PARALLELIZE_DIR)] \
     #    and investigate if they don't.
     set gcc_runtest_parallelize_counter 0
     set gcc_runtest_parallelize_counter_minor 0
+    set gcc_runtest_parallelize_limit_minor 10
     set gcc_runtest_parallelize_enable 1
     set gcc_runtest_parallelize_dir [getenv GCC_RUNTEST_PARALLELIZE_DIR]
     set gcc_runtest_parallelize_last 0
 
     proc gcc_parallel_test_run_p { testcase } {
 	global gcc_runtest_parallelize_counter
 	global gcc_runtest_parallelize_counter_minor
+	global gcc_runtest_parallelize_limit_minor
 	global gcc_runtest_parallelize_enable
 	global gcc_runtest_parallelize_dir
 	global gcc_runtest_parallelize_last
@@ -228,10 +231,10 @@ if { [info exists env(GCC_RUNTEST_PARALLELIZE_DIR)] \
 	}
 
 	# Only test the filesystem every 10th iteration
-	incr gcc_runtest_parallelize_counter_minor
-	if { $gcc_runtest_parallelize_counter_minor == 10 } {
+	if { $gcc_runtest_parallelize_counter_minor >= $gcc_runtest_parallelize_limit_minor } {
 	    set gcc_runtest_parallelize_counter_minor 0
 	}
+	incr gcc_runtest_parallelize_counter_minor
 	if { $gcc_runtest_parallelize_counter_minor != 1 } {
 	    #verbose -log "gcc_parallel_test_run_p $testcase $gcc_runtest_parallelize_counter $gcc_runtest_parallelize_last"
 	    return $gcc_runtest_parallelize_last