[testsuite] Avoid duplicate test names in sizeless tests

Jeff pointed out that using:

   N:  ... /* { dg-error {...} } */
 N+1:      /* { dg-error {...} "" { target *-*-* } .-1 } */

led to two identical test names for line N.  Fixed by adding
a proper test name instead of "".

2020-03-16  Richard Sandiford  <richard.sandiford@arm.com>

gcc/testsuite/
	* gcc.target/aarch64/sve/acle/general-c/sizeless-1.c: Add a test
	name to .-1 dg-error tests.
	* gcc.target/aarch64/sve/acle/general-c/sizeless-2.c: Likewise.

gcc/testsuite/ChangeLog

+2020-03-16  Richard Sandiford  <richard.sandiford@arm.com>
+
+	* gcc.target/aarch64/sve/acle/general-c/sizeless-1.c: Add a test
+	name to .-1 dg-error tests.
+	* gcc.target/aarch64/sve/acle/general-c/sizeless-2.c: Likewise.
+
 2020-03-16  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>
 
 	* gcc.target/arm/mve/intrinsics/mve_libcall1.c: New test.

gcc/testsuite/gcc.target/aarch64/sve/acle/general-c/sizeless-1.c

@@ -31,7 +31,7 @@ union union1 {
 
 svint8_t *global_sve_sc_ptr;
 svint8_t *invalid_sve_sc_ptr = &(svint8_t) { *global_sve_sc_ptr }; /* { dg-error {initializer element is not constant} } */
-  /* { dg-error {SVE type 'svint8_t' does not have a fixed size} "" { target *-*-* } .-1 } */
+  /* { dg-error {SVE type 'svint8_t' does not have a fixed size} "2nd line" { target *-*-* } .-1 } */
 
 /* Sizeless arguments and return values.  */
 

gcc/testsuite/gcc.target/aarch64/sve/acle/general-c/sizeless-2.c

@@ -31,7 +31,7 @@ union union1 {
 
 svint8_t *global_sve_sc_ptr;
 svint8_t *invalid_sve_sc_ptr = &(svint8_t) { *global_sve_sc_ptr }; /* { dg-error {initializer element is not constant} } */
-  /* { dg-error {SVE type 'svint8_t' does not have a fixed size} "" { target *-*-* } .-1 } */
+  /* { dg-error {SVE type 'svint8_t' does not have a fixed size} "2nd line" { target *-*-* } .-1 } */
 
 /* Sizeless arguments and return values.  */