Testsuite: Ensure pie is disabled on some tests

Testsuite: Ensure pie is disabled on some tests

Recent versions of Ubuntu and Debian default GCC to enable pie.

In dump.exp, pie will causes addresses to be out of range for IHEX.

In break-interp.exp, pie is explicitly set for some tests and assumed
to be disabled for the remainder.

Ensure pie is disabled for these tests when required.

In addition, add a pie option to gdb_compile to match the nopie option
and simplify use.

gdb/testsuite/ChangeLog:

	* README: Add pie options.
	* gdb.base/break-interp.exp: Ensure pie is disabled.
	* gdb.base/dump.exp: Likewise.
	* lib/gdb.exp (gdb_compile): Add pie option.