testsuite: i386: Require dfp in gcc.target/i386/pr101346.c

gcc.target/i386/pr101346.c currently FAILs on Solaris/x86:

FAIL: gcc.target/i386/pr101346.c (test for excess errors)

Excess errors:
/vol/gcc/src/hg/master/local/gcc/testsuite/gcc.target/i386/pr101346.c:6:1:
error: decimal floating-point not supported for this target
/vol/gcc/src/hg/master/local/gcc/testsuite/gcc.target/i386/pr101346.c:7:6:
error: decimal floating-point not supported for this target
/vol/gcc/src/hg/master/local/gcc/testsuite/gcc.target/i386/pr101346.c:9:12:
warning: implicit declaration of function '__builtin_fabsd128'; did you
mean '__builtin_fabsf128'? [-Wimplicit-function-declaration]

Fixed by requiring dfp support.  Tested on i386-pc-solaris2.11 and
x86_64-pc-linux-gnu.


2021-10-20  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

	gcc/testsuite:
	* gcc.target/i386/pr101346.c: Require dfp support.