Move strace -m/explicit location test to strace.exp

One of the build slaves shows this error running explicit.exp:

(gdb) strace -m gdbfoobarbaz
Remote failure reply: E.In-process agent library not loaded in process.
Fast and static tracepoints unavailable.
(gdb) FAIL: gdb.linespec/explicit.exp: strace -m gdbfoobarbaz

There are two big problems with this test:
1) The expected output is actually not what the test is meant to test for.
2) This test should really only run where it is supported.

This is most easily fixed by moving the test to gdb.trace/strace.exp.

gdb/testsuite/ChangeLog

	* gdb.linespec/explicit.exp: Move strace test from here ...
	* gdb.trace/strace.exp: ... to here.

gdb/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2015-08-17  Keith Seitz  <keiths@redhat.com>
+
+	* gdb.linespec/explicit.exp: Move strace test from here ...
+	* gdb.trace/strace.exp: ... to here.
+
 2015-08-15  Patrick Palka  <patrick@parcs.ath.cx>
 
 	* gdb.base/kill-detach-inferiors-cmd.exp: New test file.

gdb/testsuite/gdb.linespec/explicit.exp

@@ -86,10 +86,6 @@ namespace eval $testfile {
     add linespecs "-function myfunction -label top -line 3" $location(top)
     add linespecs "-line 3" $location(normal)
 
-    # Test that static tracepoints on marker ID are not interpreted
-    # as an erroneous explicit option.
-    gdb_test "strace -m gdbfoobarbaz" "You can't do that.*"
-
     # Fire up gdb.
     if {![runto_main]} {
 	return -1

gdb/testsuite/gdb.trace/strace.exp

@@ -390,6 +390,11 @@ if { ![gdb_target_supports_trace] } then {
     return -1
 }
 
+# Double-check that marker ID ("-m") is not mistaken for an explicit location
+# flag.
+gdb_test "strace -m gdbfoobarbaz" \
+    "No known static tracepoint marker named gdbfoobarbaz"
+
 strace_probe_marker
 
 strace_trace_on_same_addr "trace"