[gdb/testsuite] Minimize gdb restarts

Minimize gdb restarts, applying the following rules:
- don't use prepare_for_testing unless necessary
- don't use clean_restart unless necessary

Also, if possible, replace build_for_executable + clean_restart
with prepare_for_testing for brevity.

Touches 68 test-cases.

Tested on x86_64-linux.

8 files changed, 8 insertions, 13 deletions

diff --git a/gdb/testsuite/gdb.threads/access-mem-running-thread-exit.exp b/gdb/testsuite/gdb.threads/access-mem-running-thread-exit.exp
index ea228e4..b2fef9f 100644
--- a/gdb/testsuite/gdb.threads/access-mem-running-thread-exit.exp
+++ b/gdb/testsuite/gdb.threads/access-mem-running-thread-exit.exp
@@ -35,7 +35,7 @@
 
 standard_testfile
 
-if {[prepare_for_testing "failed to prepare" $testfile $srcfile {debug pthreads}] == -1} {
+if {[build_executable "failed to prepare" $testfile $srcfile {debug pthreads}] == -1} {
     return -1
 }
 
diff --git a/gdb/testsuite/gdb.threads/attach-many-short-lived-threads.exp b/gdb/testsuite/gdb.threads/attach-many-short-lived-threads.exp
index cb63257..255e483 100644
--- a/gdb/testsuite/gdb.threads/attach-many-short-lived-threads.exp
+++ b/gdb/testsuite/gdb.threads/attach-many-short-lived-threads.exp
@@ -62,8 +62,6 @@ proc test {} {
     global gdb_prompt
     global decimal
 
-    clean_restart ${binfile}
-
     set test_spawn_id [spawn_wait_for_attach $binfile]
     set testpid [spawn_id_get_pid $test_spawn_id]
 
@@ -170,7 +168,8 @@ proc test {} {
 # failure.
 set options { "additional_flags=-DTIMEOUT=$timeout" debug pthreads }
 
-if {[prepare_for_testing "failed to prepare" $testfile $srcfile $options] == -1} {
+if {[prepare_for_testing "failed to prepare" $testfile $srcfile \
+	 $options] == -1} {
     return -1
 }
 
diff --git a/gdb/testsuite/gdb.threads/break-while-running.exp b/gdb/testsuite/gdb.threads/break-while-running.exp
index 68d9bf8..de39824 100644
--- a/gdb/testsuite/gdb.threads/break-while-running.exp
+++ b/gdb/testsuite/gdb.threads/break-while-running.exp
@@ -24,7 +24,7 @@
 
 standard_testfile
 
-if {[prepare_for_testing "failed to prepare" $testfile $srcfile {debug pthreads}] == -1} {
+if {[build_executable "failed to prepare" $testfile $srcfile {debug pthreads}] == -1} {
     return -1
 }
 
diff --git a/gdb/testsuite/gdb.threads/clone-attach-detach.exp b/gdb/testsuite/gdb.threads/clone-attach-detach.exp
index 4c6813b..2232857 100644
--- a/gdb/testsuite/gdb.threads/clone-attach-detach.exp
+++ b/gdb/testsuite/gdb.threads/clone-attach-detach.exp
@@ -33,8 +33,6 @@ if [prepare_for_testing "failed to prepare" $testfile $srcfile {debug}] {
     return -1
 }
 
-clean_restart ${binfile}
-
 set test_spawn_id [spawn_wait_for_attach $binfile]
 set testpid [spawn_id_get_pid $test_spawn_id]
 
diff --git a/gdb/testsuite/gdb.threads/next-bp-other-thread.exp b/gdb/testsuite/gdb.threads/next-bp-other-thread.exp
index 1abbe58..d168f6b3e 100644
--- a/gdb/testsuite/gdb.threads/next-bp-other-thread.exp
+++ b/gdb/testsuite/gdb.threads/next-bp-other-thread.exp
@@ -20,7 +20,8 @@
 
 standard_testfile
 
-if {[prepare_for_testing "failed to prepare" $testfile $srcfile {debug pthreads}] == -1} {
+if {[build_executable "failed to prepare" $testfile $srcfile \
+	 {debug pthreads}] == -1} {
     return -1
 }
 
diff --git a/gdb/testsuite/gdb.threads/signal-sigtrap.exp b/gdb/testsuite/gdb.threads/signal-sigtrap.exp
index 92488a5..f5dc7fe 100644
--- a/gdb/testsuite/gdb.threads/signal-sigtrap.exp
+++ b/gdb/testsuite/gdb.threads/signal-sigtrap.exp
@@ -23,7 +23,8 @@ if [target_info exists gdb,nosignals] {
     return -1
 }
 
-if {[prepare_for_testing "failed to prepare" $testfile $srcfile {debug pthreads}]} {
+if {[build_executable "failed to prepare" $testfile $srcfile \
+	 {debug pthreads}]} {
     return -1
 }
 
diff --git a/gdb/testsuite/gdb.threads/step-bg-decr-pc-switch-thread.exp b/gdb/testsuite/gdb.threads/step-bg-decr-pc-switch-thread.exp
index 55ebd40..c6c6cce 100644
--- a/gdb/testsuite/gdb.threads/step-bg-decr-pc-switch-thread.exp
+++ b/gdb/testsuite/gdb.threads/step-bg-decr-pc-switch-thread.exp
@@ -34,8 +34,6 @@ if {[prepare_for_testing "failed to prepare" $testfile $srcfile {debug pthreads}
     return -1
 }
 
-clean_restart $binfile
-
 if ![runto_main] {
     continue
 }
diff --git a/gdb/testsuite/gdb.threads/tid-reuse.exp b/gdb/testsuite/gdb.threads/tid-reuse.exp
index 1d93a55..8ac1f5b 100644
--- a/gdb/testsuite/gdb.threads/tid-reuse.exp
+++ b/gdb/testsuite/gdb.threads/tid-reuse.exp
@@ -22,8 +22,6 @@ if {[prepare_for_testing "failed to prepare" $testfile $srcfile { debug pthreads
     return -1
 }
 
-clean_restart ${binfile}
-
 if ![runto_main] {
     fail "can't run to main"
     return -1