testsuite: i386: Restrict pr120936-1.c etc. to Linux

testsuite: i386: Restrict pr120936-1.c etc. to Linux

After switching the i386 check-function-bodies tests to use the new
dg-add-options check_function_bodies feature, several tests still FAIL
in the same way on Solaris/x86.  E.g.

FAIL: gcc.target/i386/pr120936-1.c check-function-bodies foo

The code differs between i686-pc-linux-gnu and i386-pc-solaris2.11 like
this:

-	.cfi_def_cfa_register 5
-	call	mcount
+	.data
+	.align 4
+.LP0:
+	.long	0
+	.text
+	movl	$.LP0, %edx
+	call	_mcount

i.e. the test expects a call to mcount, while on Solaris _mcount is
called instead.  MCOUNT_NAME is only defined as mcount in gnu-user.h and
x86-64.h, so the patch restricts the tests to Linux.

Tested on i386-pc-solaris2.11 and x86_64-pc-linux-gnu.

2025-11-23  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

	gcc/testsuite:
	* gcc.target/i386/pr120936-1.c: Restrict to *-*-linux*.
	* gcc.target/i386/pr120936-2.c: Likewise.
	* gcc.target/i386/pr120936-4.c: Likewise.
	* gcc.target/i386/pr120936-5.c: Likewise.
	* gcc.target/i386/pr120936-9.c: Likewise.
	* gcc.target/i386/pr120936-11.c: Likewise.