Compile gdb.perf/skip-prologue.c with and without debug info

Compile gdb.perf/skip-prologue.c with and without debug info

gdb.perf/skip-prologue.exp is intended to measure the performance of
skipping prologue with prologue analysis by setting breakpoints.
However, if program is compiled with debug info, GDB is smart to
skip prologue by line table from debug info, so prologue analysis
is not exercised at all.

This patch adds a parameter COMPILE to specify compiling with
debug information, otherwise, it is compiled without debug
information.

gdb/testsuite:

2016-12-09  Yao Qi  <yao.qi@linaro.org>

	* gdb.perf/skip-prologue.exp: Add parameter COMPILE.