MIPS/LD/testsuite: Correct dynamic links with VR4100, VR4300 and VR5000

Correct LD test suite failures with VR4100, VR4300 and VR5000 bare metal
MIPS/ELF targets which do not default to linking with shared libraries,
which leads to link failures like:

.../ld/ld-new: cannot find -lcomm-data
FAIL: Common symbol override test

or:

.../ld/ld-new: attempted static link of dynamic object `tmpdir/pr14170.so'
FAIL: PR ld/14170

removing:

FAIL: Build pr22471b.so
FAIL: Build pr22471
FAIL: Build pr22649-2b.so
FAIL: Build pr22649-2d.so
FAIL: Build pr22150
FAIL: PR ld/14170
FAIL: --gc-sections with __gxx_personality

test failures.

	ld/
	* testsuite/ld-elf/comm-data.exp: Pass `-call_shared' to links
	involving a shared library for `mips*vr4100*-*-elf*',
	`mips*vr4300*-*-elf*' and `mips*vr5000*-*-elf*' targets.
	* testsuite/ld-elf/provide-hidden.exp: Likewise.
	* testsuite/ld-elf/shared.exp: Likewise.
	* testsuite/ld-gc/gc.exp: Likewise.
	* testsuite/ld-mips-elf/comm-data.exp: Likewise.