gdb/testsuite/: Use -qualified in runto_main / mi_runto_main

gdb/testsuite/: Use -qualified in runto_main / mi_runto_main

In some runtimes, there may be a "main" function in some class or
namespace.  The breakpoint created by runto_main may therefore have
unexpected locations on some other functions than the actual main.
These breakpoint locations can unexpectedly get hit during tests and
lead to failures.

I saw this while playing with AMD's ROCm toolchain -- I wrote a board
file to run the testsuite against device kernels.  There, the runtime
calls a "main" function before the device kernel code is reached:

 Thread 4 "bit_extract" hit Breakpoint 1, 0x00007ffeea140960 in lld::elf::LinkerDriver::main(llvm::ArrayRef<char const*>) () from /opt/rocm/lib/libamd_comgr.so.1
 (gdb) bt
 #0  0x00007ffeea140960 in lld::elf::LinkerDriver::main(llvm::ArrayRef<char const*>) () from /opt/rocm/lib/libamd_comgr.so.1
 #1  0x00007ffeea2257a5 in lld::elf::link(llvm::ArrayRef<char const*>, bool, llvm::raw_ostream&, llvm::raw_ostream&) () from /opt/rocm/lib/libamd_comgr.so.1
 #2  0x00007ffeea1bc374 in COMGR::linkWithLLD(llvm::ArrayRef<char const*>, llvm::raw_ostream&, llvm::raw_ostream&) () from /opt/rocm/lib/libamd_comgr.so.1
 #3  0x00007ffeea1bfb09 in COMGR::InProcessDriver::execute(llvm::ArrayRef<char const*>) () from /opt/rocm/lib/libamd_comgr.so.1
 #4  0x00007ffeea1c4da9 in COMGR::AMDGPUCompiler::linkToExecutable() () from /opt/rocm/lib/libamd_comgr.so.1
 #5  0x00007ffeea1fde20 in dispatchCompilerAction(amd_comgr_action_kind_s, COMGR::DataAction*, COMGR::DataSet*, COMGR::DataSet*, llvm::raw_ostream&) () from /opt/rocm/lib/libamd_comgr.so.1
 #6  0x00007ffeea203a87 in amd_comgr_do_action () from /opt/rocm/lib/libamd_comgr.so.1
 ...

To avoid that, pass "qualified" to runto, in runto_main, so that
gdb_breakpoint ends up creating a breakpoint with -qualified.  This
avoids creating breakpoints locations for other unrelated "main"
functions.

Note: I first tried making runto itself use "-qualified", but that
caused regressions in the gdb.ada/ tests, which use runto without
specifying the whole fully-qualified function name (i.e., without the
package).  So I end up restricting the -qualified to
runto_main/mi_runto_main.

The gdb.base/ui-redirect.exp change is necessary because that testcase
is looking at what "save breakpoint" generates.

gdb/testsuite/ChangeLog:

	* gdb.base/ui-redirect.exp: Expect "break -qualified main" in
	saved breakpoints file.
	* gdb.guile/scm-breakpoint.exp: Expect "-qualified main" when
	inspecting breakpoint list.
	* lib/gdb.exp (runto_main): Add "qualified" to options.
	* lib/mi-support.exp (mi_runto_helper): Add 'qualified' parameter,
	and handle it.
	(mi_runto_main): Pass 1 as qualified argument.

Change-Id: I51468359ab0a518f05f7c0394c97f7e33b45fe69